PRE2018 3 Group3

Figure 1: Causes for train delay in the Netherlands

The Dutch railway network is one of the most crowded railway networks on the planet . An intercity leaves the station every 10 minutes. The Dutch trains are also very punctual; 90% of the trains are on time with a 5 minute tolerance. This is a rare accomplishment among railway companies. However, there is a downside to all of this; when something does go wrong, it goes wrong big time. Because the railway network is so crowded, one delay can create a congestion and in turn this can cause huge delays.

From the graph in figure 1 it can be seen that external influences (indicated by orange), railway cleaning activities (indicated by purple) and the weather (indicated by yellow) are causes for train delays in the Netherlands . As a result it can be concluded that a big cause for delay are leaves or snow on the train tracks. Trains crush the leaves beneath them, which makes the track slippery. Snow has the same effect and this is bad, because the braking distance increases tremendously. This can lead to dangerous situations. Railway companies (like the NS) try to avoid these risks by canceling their trains. However, this leads to some confusion and frustration of the travelers, since a delay caused by a couple of leaves on the tracks does not sound very dangerous.

We as a group think we can improve this sticky situation by introducing a robot to the Dutch railway network that is able to clean the tracks from obstacles like leaves and snow. This wiki describes the whole process of this project.

Group Members

Name	Study	ID Number
Max Hanssen	Industrial Design	1257269
Jorick van Hekke	Electrical Engineering	1225185
Suryanto Horlez	Computer Science	1286714
Joeri Schults	Mechanical Engineering	1266330
Jules Vaes	Mechanical Engineering	1263196

Project information

The information about this project can be found by following this link: Project information

Concept

Our goal is to design a robot which is able to autonomously clean the railway tracks from different kinds of obstacles.

The robot should be able to clean the tracks autonomously, but it should have a camera installed so that an operator can inspect it from time to time (‘man-on-the-loop’). This is also important for exceptional cases in which the robot does not know what to do.

Initially, we did not know what the major problems on the train tracks were, so we decided to contact ProRail (the company in charge of the Dutch railway network). They told us that the main obstacles on the Dutch tracks are leaves and snow, so our robot should focus on addressing these issues.

The idea is to use sweepers to collect leaves and snow. The snow can be melted which makes it harmless for the tracks, while the leaves can be compressed and used as compost. At first we wanted the robot to combat rust as well, but ProRail said the following: “It is the case that the track is ridden every day so rust formation is actually not possible. In areas where fewer trains ride, empty trains are often used at night to prepare the track so that the formation of rust cannot actually occur or is prevented as much as possible.” Based on this statement, we decided that it was not worth focussing on.

Objectives

The objectives when designing a kind of cleaning device for the Dutch railway tracks are of great importance. It is for NS and ProRail's best interest that these objectives, which we will call RPC's, ensure a product that is actually helpful. The so called RPC's - Requirements, Preferences and Constraints - are set up to determine what is important and function as guidelines for the robot's design. Using these guidelines will make sure essential matters to NS and ProRail are really thought through, so the robot functions as desired. The RPC's are stated below:

Requirements

• The robot is able to clean the tracks autonomously
• The robot is operational at any time
• The robot is able to collect the waste (mainly leaves and snow) it removes
• The robot is able to differentiate different types of waste and sort them accordingly
• The robot is able to drive up to 160 km/h
• The rotational speed of the robot's broom is at least 1160 RPM
• The robot will immediately inform authorities when an animal or person jumps on the tracks

Preferences

• The robot should be easy to maintain
• The robot's parts should be interchangeable
• The robot should be lightweight
• The robot should be compact
• The robot should be cleaning as fast and efficient as possible

Constraints

• The robot, when attached to a train, can only move in the direction the train is going
• The robot can only autonomously drive on the railway tracks at night
• The robot cannot clean solely by itself at day
• The robot cannot remove large objects like trees, debris or dead animals
• The robot cannot be wider than 3.4 meters
• The robot cannot be taller than 2 meters

Robot functions

The Dutch train tracks are very crowded in the daytime [Source]. It would be very difficult to add a slow cleaning robot to the schedule. That is why we have decided to attach the robot to the front of a train during the day. This enables us to clean the tracks, while avoiding scheduling difficulties. However, at night we want our robot to operate autonomously. At night there is a lot less train traffic, which makes it easier to add an autonomous robot to the equation. This robot should move independently along the tracks. This includes accelerating whenever possible and decelerating (for stations, obstacles, other traffic or more thorough cleaning). The robot cannot alter the track changes by itself, since this is operated by ProRail [Source]. It can ask however to change tracks.

The emphasis of this robot is on cleaning, so it is important that the robot is able to decide when it is necessary to clean (for both day and night situations). An already cleaned track does not need to be cleaned again (in most circumstances). This would be a waste of energy and that is in opposition to our preferences (see RPC’s).

We also want our robot to collect its garbage (leaves), so that it can be used as compost. When the robot has collected enough garbage, it should move to the nearest dump. This should all be done autonomously.

Daytime and Nighttime

On average there are 4500 trains riding per day to transport around 1,1 million passengers . Although a small percentage of these trains are riding through the night, most of these 4500 trains are driving during the day, as the night trains only drive once per hour between 1:00 and 5:00 in the Randstad of the Netherlands . Due to these busy train schedules during the day, it is not possible to let the cleaning robot drive autonomously on the railroads during daytime. This would only cause more delay for the NS. However, it is still extremely essential to let the machine clean the railroads during the day, because otherwise the design will not have any big positive impact on the delay problems. Hence, the only way for the cleaning machine to clean the railroads during daytime is to attach the machine onto the front of the NS passenger trains. Next to cleaning the railroads during the day, the robot can also clean during the nighttime. Because it is less crowded on the railway during the night, the robot will be able to thoroughly clean the railroads without slowing down any other trains. To improve the cleaning during nighttime, the robot will pick up and store the obstacles that block the track by following the railroad autonomously. To make the machine work during daytime and nighttime in this way, there are a few requirements which need to be met:

Figure 2: Total amount of freight trains in the year 2017

• It needs to be attachable to the front of the NS trains during daytime.
• The sight of the machinist cannot be blocked by the machine during daytime.
• It cannot slow down the speed of the train during daytime.
• It needs to be suitable and appropriate to pass by the platforms of the stations during daytime.
• It needs to be detachable from the front of the NS trains during nighttime.
• It needs to be able to move forward on the railroads by itself during nighttime.
• It needs to have a storage place to store all the obstacles found during nighttime.
• It needs to fit in the night train schedule of NS.

To meet the requirements of being able to both attach and detach from the NS trains, it needs to adapt to the front coupler of all the different NS train models. Luckily at the moment all the different Intercity and Sprinter model trains of the NS use the same type of Scharfeneberg coupler . This Scharfenberg coupler is an automatic coupler which can be activated or deactivated from the machinist cabin . The design of the cleaning machine also needs to fit with the requirements of not blocking the sight of the machinist and being suitable for platforms. This will be elaborated when developing the final design for the machine. However, from these two requirements it can already be made clear that the machine itself should not be higher than around 1.5 meter for the machinist’s sight, and not be wider than around 3 meter to fit in between platforms at stations . Furthermore, the robot will also need it’s own wheels, as it will drive autonomously during the night. Thus, these wheels need to be set suitable for the rails which have a gauge of 1435 mm . Next to the design of the machine itself, there also needs to be a design for a storage system for storing the obstacles during the night. The storage place for these obstacles needs to be big enough to fit in all the obstacles, but small enough to be able to ride the railroads. Hence, the maximum height and width of the storage place is around 4.5 meters high and 3 meters wide . The maximal length and weight of the storage place is depended on the motor within the machine. Furthermore, the adaptation to the passenger night trains that drive through the Randstad is possible. However, next to these passenger trains, there are also many freight trains that ride on the tracks daily. According to a report of Prorail, in 2017 there have been riding more than 20.000 freight trains over the same railroads in that year, see figure 1 . Moreover, it can be seen that the rail tracks with the most delays are in the Randstad area in between Amsterdam, Rotterdam, Den Haag en Utrecht . This is the same area as where the most night trains are riding. Therefore, the robot needs to clean this area extra thoroughly. Hence, it will be more effective to attach the cleaning machine onto the night trains which are traveling in the Randstad. This will prevent extra delays, as the cleaning machine will not drive autonomously within this busy train schedules in the night of the Randstad. However, outside of the Randstad the cleaning machine will still have the possibility to drive autonomously to clean the railways, as there are no passenger trains active in the night.

Why a robot?

This robot focuses solely on cleaning tracks for snow and leaves by using brushes. This is a relatively easy task for a robot, since the environment (train tracks) is structured. It is thus not very hard to program a robot to perform this task. All in all a robot is cheaper than a human employee, since they require wages, while a robot can do the same boring work every day [Source + calculations].

The Dutch train tracks are very crowded in the daytime . It would be very difficult to add a slow cleaning robot to the schedule. That is why we have decided to attach the robot to the front of a train during the day. This enables us to clean the tracks, while avoiding scheduling difficulties. However, at night we want our robot to operate autonomously. At night there is a lot less train traffic, which makes it easier to add an autonomous robot to the equation. This robot should move independently along the tracks. This includes accelerating whenever possible and decelerating (for stations, obstacles, other traffic or more thorough cleaning). The robot cannot alter the track changes by itself, since this is operated by ProRail [Source]. It can ask however to change tracks. The emphasis of this robot is on cleaning, so it is important that the robot is able to decide when it is necessary to clean (for both day and night situations). An already cleaned track does not need to be cleaned again (in most circumstances). This would be a waste of energy and that is in opposition to our preferences (see RPC’s). We also want our robot to collect its garbage (leaves), so that it can be used as compost. When the robot has collected enough garbage, it should move to the nearest dump. This should all be done autonomously.

Reasons why a robot is better than a human:

This robot focuses solely on cleaning tracks by using brushes. This is a relatively easy task for a robot, since the environment (train tracks) is structured. It is thus not very hard to program a robot to perform this task. All in all a robot is cheaper than a human employee, since they require wages, while a robot can do the same boring work every day [Source + calculations]. A robot is also able to operate 24/7 while a human would get tired. As robots do not get tired, there will not be absenteeism. A robot also does not shake like a human would while preforming a task like they would when it's cold therefore the robot will do the task more precisely then a human. Moreover, a robot can see better at night, which allows them to clean the tracks better.

Furthermore, robots can make faster decisions than humans. This enables them to make better decisions on when it is important to clean and thus saving energy [Source].

USE aspects

Users

For this project the focus has been put on the railroads in the Netherlands. This decision was made, because it is only possible to design the product for one certain type of railroad system. At this stage designing a product which can be used globally by adapting to different types of railway systems is too advanced. Furthermore, the project would have too many potential users to focus on, as they will differ per country. Therefore, it was decided to stick to the Netherlands, as this is the country which we had the most experience with. Although it was decided to keep the focus in this specific area, there is still a wide variety of users. For this design there are people who can use and influence the design directly, as well as people who get influenced indirectly by the design. Hence, a distinction can be made between primary and secondary users. The term primary users will be used to refer to the group of users who are directly interacting with the design. The term secondary users will be used to refer to the group of users who are not directly in contact with the design but still affected by it. The distinction between these two different users will be made more clear by defining both groups.

Primary users

For this design, the group who buys, uses and introduces the design into its target scenario are considered as the primary users. Hence, the organisations who are responsible for the railway system in the Netherlands belong to this groups. Thus, only Prorail is the primary user, as they are the ones responsible and can make direct changes to the railway system. The NS can not be fully considered as a primary user, as they only make use of the railway system, but are not responsible for the railroad itself. Prorail are the ones responsible for the construction, maintenance, management and security of the railway system in the Netherlands. When a product with the aim to clean the railroads is used, Prorail is the main company to introduce, use, and interact with the product.

Secondary users

For this design, the people who get influenced positively or negatively by this design in an indirect way are considered as the secondary users. As mentioned above the NS is not considered as primary user, instead NS can be considered as a secondary user. They make use of the railway system in the Netherlands by transporting people from location to location with trains that drive on the railroads. Therefore, they will not be in direct contact with this design, as they will only get positively influenced but cannot influence the design itself directly. The use of the design on the railroads will be a great advantage to the NS, as it will make the railroads free and safe which reduces the delay for trains of NS.

In addition to NS, this reduction in delay also has a positive effect on the users of NS. These users are people who make use of the trains of NS as transportation to get to their destination as fast as possible. Although NS and Prorail are in charge of the trains and railways in the Netherlands, this group of travelers is important and can also be considered as secondary users.

Occasionally, trains of foreign companies such as Thalys or NMBS also make use of the railway system in the Netherlands. As a result, these foreign train companies can also be considered as secondary users. However, this group of users will not be further addressed, as the main focus is put on the companies NS and Prorail.

Society

Obstacles on the railroads, which cause a delay for many travelers, can be considered as a problem to society. In some occasions the delay can come up to major amounts of time or even cancellations of trains, which leads to missing important meetings or appointments. Moreover, this can form a challenge to the government, as the NS is a Dutch state-owned company. This means that the government has significant control over the NS through majority ownership. For this reason, one of the main aims of the government is to make transportation more accessible to its users. To be able to make transportation on railway more accessible, the delays of trains need to be taken care of. This design can help with solving this challenge to society. The design of this project can not fully solve the challenge of it, as there are many factors which have an influence on causing delays in transportation. However, this design will still have a positive impact on this relevant problem. It has the potential to play a big role in the future of railroad maintenance which is beneficial to society.

Enterprise

In the USE aspects, enterprise is considered to be the relevant companies that are connected to the project. The main aim for these enterprises is to make as much profit as possible. The previously discussed primary user Prorail can be seen as a relevant enterprise to this design. Although currently Prorail is still a government task organisation company that is part of NS, the Ministry of Infrastructure and Water is planning to make Prorail a public law independent administrative in 2021 . As a result Prorail will become an organisation which conducts governmental tasks, while they are not under authority of the Dutch government. Hence, in the future Prorail will look at this design from a business perspective. They will only decide to make use of this design if it is profitable for the company. Unless they are forced by the government as they will be an independent administrative. Therefore, the design is required to be efficient in general, as well as cost-efficient so that Prorail will have good consequences from using the product.

Design

Prototype

Figure 3: First idea for the prototype

The first idea for a prototype was made with SketchUp, as can be seen in Figure 3. The model uses a standard NS Intercity (Bombardier TRAXX) locomotive for scale and context. Since the robot will block the locomotive's headlights, it is provided by a pair. It also contains rear lights of course, since it will be able to drive on its own on the tracks. The robot is equipped with dual opposite-rotating brooms which are placed up front. The robot will also be equipped with sensors (cameras) on the front, on the sides and on the back to maximize visibility. Notice the robot is much smaller in height than the locomotive, this is make sure the tracks are still visible for the engineer. The prototype can be as wide, if not wider than the locomotive itself, if it only stays within a 3.4 meter margin as mentioned in the RPC's. This margin is there to make sure vehicles on railway tracks can safely go through tunnels for instance without any hindrance.

Coupling system

Figure 4: Coupler system of the NS Scharfenebrg coupler

As discussed in the previous daytime nighttime section, the robot needs to adapt to the front coupler of all the different NS train models to both attach and detach from them. At the moment NS trains use a Scharfenberg coupler which is an automatic coupler that can be activated or deactivated from the machinist cabin. After getting in contact with the NS through customer service online, it was confirmed that the Scharfenberg coupler are mostly used. Additionally, the NS online customer service gave us the information that another type of coupler called BSI is also used for DDZ and DD-AR train models. Next to this BSI coupler, the NS also use the screw coupling for some trains. Although they use multiple types of couplers, it is the most efficient if the cleaning machine is adapted to one type of coupler. Hence it was decided to use the Scharfenberg coupler, as this is the most used coupler by the NS. Furthermore, the NS have given us a product sketch of the Scharfenberg coupler which they use, which can be seen in figure 3.

At the moment there are 6 types of main Scharfenberg couplers on the market: the type 10, type 35, type 330, type 430, type 55 and the type 140 . The cleaning machine does not necessarily have to have the same type of Scharfenberg couplers as the train to which it needs to connect. There are transitional couplers, such as the modular transitional coupler, that can connect two different type of Scharfenberg couplers . This modular transitional coupler separates the two couplers into two separate head and an adapter that forms the step. The two heads can be connected to each other directly, which makes it possible to connect coupler heads of any kind and at different heights into the transitional coupler. As a result, a suitable type of Scharfenberg coupler can be chosen for the design of the robot.

• The type 10 Scharfenberg coupler is often used by railway companies, and is reliable due to its high strength and large gathering range laterally and vertically.
• The type 35 is suited for vehicles without a compressed-air system, so for fully electrified vehicles.
• The type 330 is often used in light rail applications due to its small size. However, it is still a strong and reliable coupler.
• The type 430 is ideal for low floor trams and monorails, because of its compact and lightweight construction. Furthermore, it can fit behind the front covers.
• The type 55 and type 140 are specifically made for high loads in rough environments.

For the robot, the best option will be the type 330 or the type 430, as these two types are ideal for lighter sized vehicles and can still deliver a strong support. Furthermore, these types are not as big as the other types and can fit behind the front covers. However, the type 330 can transmit a buff load of 800 kN and a draft load of up to 600 kN, and the the 430 can transmit compressive and tensile forces of up to 300 kN. Further calculations need to be done with these statistics, after the full design and weight load of the robot have been predicted, to see whether these couplers can hold up to the forces caused by the robot.

Obstacles

Snow

Problem

In very cold periods like in the winter, snow and ice can build up on the tracks. The ice can block movable parts of the track and coat over the power lines or the third rail, preventing trains from drawing the power they need to run. Also icicles on bridges and tunnels can cause serious damage to passing trains. All these problems can cause the trains to have delays.

When a train has to slow down as it approaches a station or set of points, snow can get compact on the rails and turn into solid ice. This not just clogs the point but also enables them from working and can coat the rails, disconnecting the trains from getting the needed power. Ice sheets are a risk for dislodging and damaging trains, the steel rails can freeze together when it gets to cold what makes the signals stay red preventing the trains to move. When snow drifts are deeper than 30cm , trains can no longer run safely unless they have snow ploughs.

Solution

Bleach,Salt

Using these products we can lower the rate of freezing cause during the freezing and melting process some water molecules freeze while others melt, replacing each other in a state of equilibrium, while when one of these products are added in the mixture it disrupts this equilibrium.

Laser

CO2 Lasers can be used to melt ice and snow with a wavelength of 10.6 μm ,which ice strongly absorbs, to drill (via melting) through ice. The resulting drilling speed is measured at several irradiation intensities, ice-snow densities, and beam angles relative to the horizontal axis. The speed increases nearly in proportion to the laser intensity. For the laser to be able to remove the snow, it must be able to handle the maximum snowfall in the last 7 years the maximum snowfall on a day is 8cm on the 14th of January 2013. We first want to know how much snow the laser should be able to melt in a second. We calculate it by looking at the speed of the train which is 160km/h, which is equal to 160 000 m/h , divided by 360 we get 444,44 m/s. The width of the rails is 1,565m, calculating all the numbers together we get around 55,64 m^3/s which is the number of cubic meters snow that has to be melted in a second in order for the train to be moving at the same speed when there is a layer of 8cm snow on the rails. According to aqua-calc 1m^3 = 481 000g for compact snow and 160 000g for freshly fallen snow. This gives us 26 762 840g to be removed in a second if the snow is compact and 8 899 200g if the snow is freshly fallen. To know how much energy is needed to melt down the snow we must know first how much is the Latent heat of fusion for water which is 333 joules per gram , this gives us 8912025720 joules for compact snow and 2964499200 for freshly fallen snow. We want to know the wavelength of the laser therefore we needed to know the energy, by using Planck's equation we can figure out the wavelength . By using the wavelength equation and the energy equation we see that they have the frequency in common , it shows that we can express the frequency in energy divided by Planck's constant which gives wavelength = Planck's constant times speed of light divided by the energy, For freshly fallen snow we get a wavelength of 6,705.10^-26 nm and for the compact snow we get 2,23.10^-26 nm. The wavelength we get are corresponding to the wavelength of Gamma-rays. Lasers having Gamma-rays are at the moment still not developed as it still is a challenge for scientists however in the futur it might be possible according to Cordis .

Snow plough

A snow plough can be used to clear the train rails when there is more than 30cm of snow, we could use this one the robot to make it possible to clear the rails for other trains, at the moment this is already installed on normal trains when the snow is higher than 30cm.

Leaves

Problem

In the Autumn trees will drop their leaves which might land on the railway. At first the leaves will not cause any trouble, but during the day they will cause problems. If the leaves which landed on the railhead become moist and heavily compressed by the passing trains, they will result in a low-friction coating. Due to this low-friction coating the railway becomes slippery and the wheels of the train starts to block when it is starting to brake. Due to this blocking one side wheels will experience more wear than the other sides which results in “square-wheels” . These “square-wheels” need to be repaired in workshop which costs time and money. Due to the malfunctioning and repairing of the train wheels less trains will be deployed on trajects which is not preferred by the travellers. Another problem due to the low-friction coating is that it can take up to 800 meters extra to come to a total stop .

Solutions

Leaf blower

A leaf blowers is used to blow loose leaves away from their initial position. This could be useful for the trains because they can blow the leaves away from the railhead. But this is not an option anymore. Due to the high compressing the leafy moist is stuck to the railway, therefore the leaf blower is not able to blow the leafy moist away .

Laser

Lasers are used for all kind of operations but when operating at a wavelength of 1064 nm it becomes useful for the railway. Due to a carefully designed optical set-up of mirrors and lenses the laser was able to produce a series of pulses, 25.000 per second, at this wavelength which cleared the track from debris. The highly compressed leaves on the railway absorbs the pulses, each with a temperature of 5.000 Celsius degrees. Due to this high temperature the leaves heats up rapidly which causes it to expand and lift of the railway . In our project we prefer one solution which solves the leafy issue but also the snow issue. As also stated in the snow part a laser would take to much time to remove the snow and therefore the laser will not be used in this project.

Pressure washer

A pressure washer is used to clean object from a dirty layer which is stuck to the surface. Therefore the pressure washer can be used to remove the compressed layer of leaves from the railway. An example of a product which is already tested is the Nilfisk-ALTO developed by Nilfisk-Advance for the Banedanmark, the railway organization in Denmark. The Nilfisk-ALTO has a 7000 liter water tank and operates at a pressure of 500 bar and sprays 40 L/min. The wagon achieved to clean the railway from the leaves when it runs at an operating speed of 45 km/h . Due to the large amount of water that needs to be stored the pressure washer is not an option for our robot. The robot is attached to the front of a train during the day and therefore a container filled with 7000 liters of water will impedes the view of the machinist.

Traction Gel Applicator

Traction gel applicator (TGA) is a substance which consists out of sand, metal particles and starch . The TGA system consists of a sensor and 50 meters further the cabinet. The cabinet contains the electronics, a pump, a delivery hose, the substance and is solar powered. The sensor, which gets triggered by the wheels of the train, sends a signal to the cabinet that a train is coming. The pump of the cabinet then places some TGA on the railhead via a delivery hose. When the train passes the cabinet the TGA gets stuck on the wheels and this gives the train more traction for a short distance, 60 to 200 meters . Due to this short distance the TGA cabinets are typically placed at the entries and exits of a train station .

Sweeper

Figure 4: The horizontal sizes of the LSRPM 132 M

Figure 6: The pulley alignment of the LSRPM 132 M using a belt

Figure 5: The width and space of a railway

Figure 6: The height of the leaves on the railhead

Figure 7: The different lengths which are used in the calculations

Figure 8: The relation between the pressure in megaPascal MPa and the developed torque in Nm Td

Figure 9: The relation between the developed torque in Nm Td and the power in megaWatt MW

A sweeper can be used to remove dirt from surfaces. The brushes can be made out of metal (steel), polypropylene or pig’s bristles. For brushes used to clean the railway the bristles are made out of steel or polypropylene and the sweeper operates at a high torque which makes it possible to remove snow, coal, stones, dust, sand, leaves, trash and dirt from the railway . When the high-speed rail is left out the maximum speed a train can achieve in the Netherlands is 160 km/h . This means that the brushes have to rotate at a speed higher than 160 km/h. For this research a minimum speed of 200 km/h is a requirement for the brushes. A common diameter for the broom is 915 mm, the broom diameter of the Dymax rail sweeper is equal to 915 mm and the diameter of the KM90/120 is also equal to 915 mm. Therefore the brush diameter of the robot is fixed at 915 mm if the brush is placed horizontally over both railheads. Most motors have their speed specification in rotations per minute (RPM). The speed in km/h of the motor depends on, in this case, the diameter of the brushes. The diameter is fixed at 915 mm and the minimum speed is 200 km/h therefore the minimum RPM can be calculated using the following equation

v = d x RPM x 0.001885 (1)

where v is the speed in km/h, d is the diameter in cm and RPM is the speed in rotations per minute. Using 200 km/h and 915 mm for the diameter a minimal RPM of 1160 is needed to operate at a sufficient speed. When searching for already used rail sweepers the RPM is too low to use in our robot. After some research the LSRPM 132 M permanent magnet synchronous motor (PMSM) was found which has the following important specifications in the operation range of 1500 RPM:

• Rated power P_n = 12 kW
• Efficiency η = 92.0 %
• Rated torque T = 69 Nm
• Rated current I = 21 A
• Weight = 49 kg

The sizes are shown in picture ???. The RPM of a motor can be obtained using the following equation

RPM =P/T (2)

where P is the power in Watts and T is the torque in Nm. Filling in the data of the LSRPM 132 M a RPM of 1660 is obtained. Converting this RPM into km/h using (1) gives 286.44 km/h. This is a high enough speed to operate which means that the motor is also able to operate at a lower RPM which consumes less power, this also results in a lower required current.

Another possible placement of the sweeper is to place it vertical and use two sweepers instead of one. The new diameter of the brushes is determined using the knowledge about the railway. The railway has a width inside width of 1435 mm and a heart-to-heart width of 1500 mm . This means that the width between the outsides of the railway is equal to 1565 mm, this is also show in the figure ???. To clean the rail-head from the compressed leaves and the snow, which also lays between the two rail-heads, the diameter of one sweeper has to be half the width of the outside to outside. The minimum diameter which cleans the whole surface is equal to 782.5 mm. To foresee a problem which is caused by the brushes touching each other a diameter of 770 mm is used. The advantages of placing the brushes vertical is that less torque is needed per sweeper because the two sweepers now clean one railhead each instead of one sweeper two railheads. Another advantage of using two sweepers is that it is not needed to place the sweeper a bit diagonal. When a horizontal sweeper is used it is needed to place it a bit diagonal to move the leaves, but mostly the snow, next to the railway. If the sweeper is not placed diagonal the leaves and snow are only moved forward which means that the sweeper is constantly removing the same leaves and snow. By using the vertical sweepers the leaves and snow are moved to the direction in which the brush is rotating. This means that, from the perspective of the machinist, the left brush has to rotate counterclockwise and the right brush clockwise to move the leaves and snow next to the railway.

The power transfer from the motor to the brushes will be done using a belt which is also suggested in the data sheet of the LSRPM PMSM . The exact placement of the belt is shown in figure ???. On one side of the motor an extra gear is needed to make the brush rotate counter-clockwise.

The next important part of the sweeper is the material of the brushes. Common materials for the bristles are steel and polypropylene. The leaves are highly compressed and therefore strong bristles are needed. Steel bristles are strong but also affect the railway itself, metal on metal friction. The goal is to remove the leaves from the railhead while the rail itself in not additionally damaged, therefore the steel bristles are no option. Polypropylene can be soft but also hard, for our problem the hard polypropylene is the solution.

The required specifications of the motor are calculated in the following parts.

Pressure

The leaves are compressed to the railhead by the trains themselves. To calculate the maximum pressure in Pascal that the leaves are compressed the surface and the weight have to be calculated. The four-coach configuration of the Regiorunner weighs 226 ton. Every waggon has 8 wheels which means a total of 32 wheels for the four-coach configuration. Dividing the total weight over the wheels gives a weight of 7062.5 Kg per wheel. The diameter of one wheel is 1000 mm, this gives a wheel radius of 500 mm. To calculate the area which is compressed by the train the height of the leaves on the railhead needs to be known. A research of L. R. Goodes, T. J. Harvey, N. Symonds and T.G. Leighton on the leaves on the railhead shows a diagram shown in Figure ??? which displays the height of the leaves. From Figure ??? can be concluded that the highest point is 20 µm which will be used in the following calculations. An illustration of the lengths for the following calculations are shown in Figure ???. First the height a between the middle of the wheel and the highest point of the leaves is calculated using

a = r-h, (3)

where r is the radius of the wheel and h is the highest point of the leaves on the railhead. Then the length from the middle of the wheel to the point where the radius r achieves the height a can be determined using pythagoras

b = sqrt[(r^2)-(a^2)]. (4)

Using the length b the total length which compresses the leaves L can be calculated using the following equation

L = 2b. (5)

To calculate the area A which is compressed by the train the length 'L is multiplied by the width of the railhead w

A = L x w. (6)

To calculate the pressure which is expressed on the leaves the weight per wheel has to be converted from Kg to Newton which is done with the following equation

N = 9.81 x M_w, (7)

where N is the weight per wheel in Newtons and M_w is the weight per wheel in Kg. The pressure Pa in Pascal is finally determined using

Pa = N/A. (8)

When the train has passed the pressure on the leaves will decrease but the leaves are more stuck to the railhead than before. When the leaves are wet some amount of water is pressed out of the leaves which makes it stuck even more to the railhead.

Torque

The torque depends on how heavy or stucked the leaves are to railhead. In this calculation the torque is determined using an object from which the bristles do not bent, this means that for the real-world problem the torque needed is higher than calculated. First the effective radius of the sweeper which cleans/moves the leaves is calculated. In the most extreme case this is equal to half the width of the railhead. This is then multiplied by the mass of the of the compressed leaves. This will lead to the following equation

Td = N x w/2, (9)

where Td is the required developed Torque, N’ is the mass of the compressed leaves in Nm and w is the width of the railhead. Figure ??? shows the relation between the pressure in megaPascal MPa and the developed torque in Nm Td. The shaft torque Ts is determined using the efficiency of the motor which will be equal to the efficiency of the LSRPM 132 M, in this case 92.0%. The equation for the shaft torque is equal to

Ts = Td/efficiency, (10)

Power

The required power is determined using the fixed speed in RPM calculated with (2). The equation for the power will look like this

P = Ts x RPM (11)

The relation between the developed torque in Nm Td and the power in megaWatt MW is shown in Figure ???.

Conclusion

When the equations are filled in with the data from the Regiorunner and the knowledge from the research of of L. R. Goodes, T. J. Harvey, N. Symonds and T.G. Leighton on the leaves on the railhead a pressure of 59.5859 MPa is found. This leads to a required developed torque of 4503.4 N/m. When the speed of the sweeper is fixed at 200 km/h a required power of 6.2054 MW is obtained. The full implemented calculation can be found in appendix B. The LSRPM 132 M permanent magnet synchronous motor does not have the required specifications; it has a to low power and torque. The required power which goes into the megaWatts in not possible together with a developed torque of 4503.4 N/m and therefore the sweeper will not be used in the final product.

Rust

During the beginning of this project it was thought that rust also caused problems and that it should be removed with the use of our robot. When we contacted Prorail it became clear that rust is not a critical problem, due to the continues driving of the trains the rust has no time to be created. From this information it is decided to not focus on rust anymore.

Component list

In this part of the report a list of components shown which are needed for the product.

Electrical

Product	Amount	Price per unit	Mass per unit	Picture
LSRPM 132M	1	$5.445,-	Mass 1	Picture 1
Coupler system type 430	2	Price 2	Mass 2	Picture 2
Computer	Amount 3	Price 3	Mass 3	Picture 3
Speed sensor	1	Price 4	Mass 4	Picture 4
Product 5	Amount 5	Price 5	Mass 5	Picture 5
Product 6	Amount 6	Price 6	Mass 6	Picture 6
Product 7	Amount 7	Price 7	Mass 7	Picture 7
Product 8	Amount 8	Price 8	Mass 8	Picture 8
Product 9	Amount 9	Price 9	Mass 9	Picture 9

Non-electrical

Product	Amount	Price per unit	Mass per unit	Picture
Hard polypropylene brushes with diameter 770 mm	2	Price 1	Mass 1	Picture 1
Base	1	Price 2	Mass 2	Picture 2
Wheels	4	Price 3	Mass 3	Picture 3
Frame	1	Price 4	Mass 4	Picture 4
Product 5	Amount 5	Price 5	Mass 5	Picture 5
Product 6	Amount 6	Price 6	Mass 6	Picture 6
Product 7	Amount 7	Price 7	Mass 7	Picture 7
Product 8	Amount 8	Price 8	Mass 8	Picture 8
Product 9	Amount 9	Price 9	Mass 9	Picture 9