Railroad Train Guidance System (RTGS)

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RFP*: Train Guidance System

* RFP is an acronym for Request For Proposal. Internationally, RFPs are called ITTs, an acronym for Invitation To Tender. Companies and governmental agencies use RFPs to solicit new business.


Introduction and Overview:

The East side of Manhattan has grown steadily since the early 1940s, when the area began to change from an industrial district into a residential neighborhood. Since the two elevated train lines over Second (1942) and Third (1956) Avenues were taken down, the area has been served by the Lexington Avenue line alone. Passenger loads on the 4 and 5 Express trains exceed transportation guidelines. Plans have been proposed to alleviate this congestion since the early 1930s. A plan developed in the 1960s led to the construction of several tunnel segments, but was abandoned during the city's fiscal crisis in the 1970s. Many ideas have been proposed and abandoned, due to strong opposition by various groups. Finally, plans for a Second Avenue Subway Line have gone forward. Running from 125th Street to 63rd Street, the subway will continue south to Lower Manhattan and Brooklyn via the existing Broadway Line. The Second Avenue Broadway Line will be a boon to those who live and work on the East Side of Manhattan, finally having an alternative to the frenzied congestion of the Lexington Avenue Subway.

The Metropolitan Transportation Authority (MTA) New York City Transit is responsible for the safe and efficient transportation of hundreds of thousands of New Yorkers each day. The vast and complex subway system is home to dozens of train lines and hundreds of stations. Currently, many capital construction projects are underway, including the East Side Access MTA Long Island Railroad Grand Central Connection, which will connect the Long Island Railroad's Main and Port Washington Lines to a new Terminal under Grand Central Station in Manhattan, and the extension of the 7 Train to the far West Side of Manhattan to serve the proposed football stadium for the New York Jets.

The Second Avenue Broadway Line is in the planning stages. MTA New York City Transit is requesting proposals for the design of the switches and signals for this project. You are competing for a contract to design and program the logic responsible for safely guiding the trains along the Second Avenue Broadway Line. A major part of the competition is to demonstrate your capabilities by using digital logic to efficiently control a section of track specified by MTA New York City Transit. For more information, see http://www.mta.nyc.ny.us/capconstr/.

Your plan must be innovative. The winning proposal will be the one that combines solid engineering with a deep understanding of the problem and its solution. For this project, you’ll be writing a proposal cover letter. Your letter should include information on your company and its lead developers with at least one reference to a previous project.

Please refer to the EG specifications for writing the proposal cover letter. The format outlined in the Technical Communication section of the online EG manual is the one you should use.

Prerequisite

If you have not already done EG1004 Lab 5: Digital Logic, you will probably find the rest of this document confusing. If you have not already done Lab 5, stop now and read Section 5.1: Overview and Section 5.5: Sample Problem in that lab. Then come back and read this document.

Specifications:

As part of this project, you are required to use digital logic to design Boolean equations that will be used to control the track switches along the right of way. This includes creating truth tables, transforming these truth tables into simplified Boolean equations, and implementing your equations with digital logic, using LabVIEW to control the train track, allowing a locomotive to safely navigate the track from left to right, and back again.

The route the train can take is controlled by track switches arranged into 8 sectors, as shown in Figure 1. Sectors 1, 4, 5, and 8 are called “X�? sectors because the combination of the four track switches make a letter “X�?, and the train can either travel straight or cross over to another track. Sectors 2, 3, 6, and 7 are called “Y�? sectors because the sector consists of a single track switch that looks like the letter “Y�?, and can choose one of two tracks to merge with one track.

Train1.gif

Figure 1: Track Layout

Your logic design will throw the track switches to allow a train to travel from Terminal Station L to Terminal Station R, reverse direction, and travel from the Terminal Station R back to Terminal Station L. The train can leave from either side of Terminal Station L, and can arrive on either side of Terminal Station R. Similarly, on the return trip, the train can arrive on either side of Terminal Station L

This trip can be made in the Normal Mode or the Reverse Running Mode. In Normal Mode, defined by MTA New York City Transit, only the Sectors 2, 4, and 6 tracks are used for travel from left to right. Sectors 7, 5, and 3 are used for travel from right to left. In summary, the train must “keep to the right�?, like cars on a highway. In Reverse Running Mode, defined by the Northeast Operating Rules Advisory Committee Rule 261, all the tracks can be used to travel in either direction.

For normal mode, the train leaves Terminal Station L, and crosses Sector 1, if necessary, to get to Sector 2. At Sector 2, you have a choice of using the inner or outer track. Since the optimal path between two points is a straight line, its ideal path would be the inside tracks of Sectors 2, 4, and Sector 6, crossing Sector 8, if necessary, to arrive on the proper track at Terminal Station R. For the return trip, the train would cross Sector 8, if necessary, to get to Sector 7. Its ideal path would be the inside tracks of Sectors 7, 5, and 3, crossing Sector 1, if necessary, to arrive on the proper track at Terminal Station L.

Your train will not be the only train running on the tracks. As part of the specifications, there will be 12 possible locations for other trains to be on the tracks. Your Boolean equations and LabVIEW programs must compensate for this, and allow your train to get through.

Train2.gif

Figure 2: Possible Locations for Other Trains

Your task is to design a digital logic system that will allow the train to travel from one end of the track layout to the other, and to return to the starting point using the designated departure and arrival tracks. During testing, your TA will place railroad cars to some of the locations, A through K, shown in Figure 2, blocking paths. Your logic will then throw the train switches (as described below) to allow the locomotive to travel from Terminal Station L to Terminal Station R, where the locomotive will stop. The TA will change the railroad cars to other locations, and your logic will throw the switches for the return trip. Note that the arrival and departure tracks of the two terminals may be dictated by cars blocking at Locations A, B, K, or L. If both tracks at a terminal are available, you can use either one.

The EG staff has already done much of the work for you, providing Virtual Instruments (VIs) that will tell you which of the locations in Figure 2 are blocked, and accepting outputs from your VI as described below to actually throw the track switches. Design a LabVIEW VI which contains a digital logic circuit that accepts the following inputs:

  • The status of each of the 12 locations, i.e., whether they are occupied or not. This information will come from a VI provided by the EG staff.
  • A switch included in LabVIEW that indicates the direction of the train's travel, i.e., from left to right or right to left.
  • A switch included in LabVIEW that indicates whether the train’s travel will be via Normal Mode o rReverse Running Mode

Your digital logic must provide the following outputs:

  • If one or more paths is available, supply the digital logic outputs for the settings of the track switches for each of the eight sectors to the VI provided by the EG staff. This VI will throw the switches according to your specification, allowing the train to travel from one Terminal Station to the other.
  • A red light included in LabVIEW on the Front Panel that illuminates if there is no path available.

After your VI has set the switches, your TA will drive the train from the Terminal Station L to Terminal Station R, and move the blocking cars. After your VI sets the switches for the return trip, your TA will drive the locomotive back to the Terminal Station L.

MICROSOFT PROJECT

Your team must create a time management plan using Microsoft Project. This plan must include all tasks related to the project. It should include at least 20 tasks. Each task must be named, assigned a duration and ranked in importance relative to the other tasks you have identified. You must begin your work by creating an MS Project plan. Follow your project plan throughout the semester. If the team falls behind schedule, explain the reasons for the delays when you present your progress reports, list the steps being taken to get the project back on track, and create a revised MS Project plan.

COST ESTIMATE/ENTREPRENEURSHIP

You will need to create a cost estimate using quotes from a reputable vendor. Examples are Digikey (http://www.digikey.com), Newark Electronics/Newark In One (http://www.newark.com), and On Semiconductor (http://www.onsemi.com). You are not limited to these vendors. This cost estimate includes prices for TTL Logic Chips for the various logic gates you use in your LabVIEW VI. When doing your cost estimate, be sure to include specification sheets from the vendors for all of the chips that you may use.

In addition, you should consider what you would do if you won the contract to implement this logic across the entire Second Avenue Subway line. Examples of things to consider are: how quickly you could design and implement the logic for each section of track, whether you would implement everything at one time or stagger deliveries, and how you would schedule ordering of parts.

MILESTONES

As you work on your project, you will be required to present periodic reports on your progress. We call these Milestones. All the items assigned in each Milestone are called deliverables. These deliverables often consist of a combination of written submissions, presentations, and demonstrations.

Milestone 1

(Introduction to Digital Logic)

For this milestone, we will create a plan for the train to leave Terminal Station L. When the train leaves the terminal, the Sector 1 switch is in place to allow the train to travel outbound via Sector 2 or Sector 3. You will be creating a Boolean Equation to determine which Sector to use, based on which of the tracks is blocked by railroad cars.

Train4.jpg

Figure 3: Terminal with switch

Train6.jpg

Figure 4: Terminal with locomotive (blue) leaving with a blocking car ahead (yellow)

Here are the Boolean Variables you will need to create the equation:

  1. Let T represent the track that the train is on at the terminal. If T=0, the train is on the bottom track, and if T=1 the train is on the top track.
  2. Let A represent a train blocking the bottom track after the switch.
  3. Let B represent a train blocking the top track after the switch.
  4. If A or B = 0, the corresponding track is free of obstacles. If A or B = 1, the corresponding track is blocked.
  5. Let S represent the status of the switch. For simplicity, there are only two values. When S=0, any train passing over the switch will stay on course. When S=1, any train passing over the switch will be diverted to the other track.
  6. Let C represent whether or not you can proceed through the switch to one track or the other. When C=0, the right of way is blocked, and the train cannot proceed. When C=1, the track is clear, and the train can proceed through the switch.


Create a truth table showing every possible outcome. (Hint: How many possibilities should there be?) Create a Boolean equation based upon your truth tables. Create a K-Map and use it to simplify the Boolean equation (if possible). See Lab 5 in your lab manual for further assistance. Remember, you are solving for S and C.

For the Milestone 1 presentation, prepare a brief description of the problem, what your goals are, and how you will accomplish these goals. In addition, write up a cost estimate of your implementation for leaving Terminal Station L, plus an estimate of the overall project by multiplying this cost by an appropriate factor based on the additional complexity of the overall train layout. The presentation should also include your MS Project chart as well as what you plan to do next.

Milestone 1 Deliverables: Initial proposal and presentation. Prepare a brief description of the problem, what your goals are, and how you will accomplish these goals. Calculate a cost estimate of your implementation for leaving Terminal Station L, plus an estimate of the overall project by multiplying this cost by an appropriate factor based on the additional complexity of the overall train layout, and an MS Project plan. In your Initial Proposal, briefly decribe in complete sentences the goals and specifications of your design project. Be sure to include any special features and benefits of your design.

Note: Whenever you revise your drawing(s), your cost estimate, or your MS Project plan, you must include the initial drawing, the initial cost estimate, or the initial MS Project plan, in addition to the revision.

Look Ahead: What tasks do you plan between now and Milestone 2?

Milestone 2

Prepare the truth tables and Boolean equations that will satisfy the input and output specifications provided.

Milestone 2 Deliverables: A copy of your presentation slides that includes a brief description of the problem, what your goals are, and how you plan to accomplish these goals, a revised cost estimate of the overall project based on your solution, your revised MS Project plan, and your signed component testing form.

Note: Whenever you revise your drawing(s), your cost estimate, or your MS Project plan, you must include the initial drawing, the initial cost estimate, or the initial MS Project plan, in addition to the revision.

Look Ahead: What tasks do you plan between now and Milestone 3?

Milestone 3

Prepare two LabVIEW VIs. The first VI will use your Boolean equations to show how the track switches will be set. Instead of inputs being provided by the VI given to you by the EG staff, use Boolean switches in a LabVIEW front panel to indicate which track locations are occupied by cars. Instead of sending outputs to the other VI provided by the EG staff, use lights on the front panel to indicate which switches are set to divert trains traveling over them.

The second LabVIEW VI will be your actual project LabVIEW VI, which will interface with the VIs provided by the EG staff. This program will be a modification of the first LabVIEW VI. Refer to the Train Electrical Specifications for more information.

Milestone 3 Deliverables: A copy of your presentation slides that includes a brief description of the problem, what your goals are, and how you plan to accomplish these goals, a revised cost estimate of the overall project based on your solution, and your revised MS Project plan.

Look ahead: What tasks do you plan between now and the completion of the project?

COMMISSIONING

Load your VI into the PC connected to the train layout, and interface it with the VIs provided by the EG staff. Your TA will then place train cars in various locations, and position the locomotive on a track at Terminal Station L. The TA will first test your program using Normal Mode. Set the Boolean switches on your LabVIEW front panel so your VI has this information. When the TA is finished, your VI should read the Boolean switches and locations of the train cars via the VI provided by the EG staff, calculate the proper track switch positions, and output the results to the other VI provided by the EG staff. This VI will set the track switches according to your specifications. The TA will verify that the path you have established will work. Once your VI establishes a successful path, the TA will drive the locomotive from left to right. After the locomotive arrives on the proper track at Terminal Station R, the TA will rearrange the cars blocking paths for the return to Terminal Station L. Set the Boolean switches on your LabVIEW front panel to indicate this information. Your logic should read the blockage information from the VI provided by the EG staff and set the track switches to the proper position. The TA will verify that you’ve established a good path, and will drive the locomotive back to the Terminal Station L, arriving on the proper track.

After you have tested your VI with normal running, the TA will then test your VI in Reverse Running Mode. The procedure will be the same as the Normal Mode, with the exception of Reverse Running.

Finally, your TA will test your VI such that it indicates no path correctly. If your VI completes all tests successfully, you will be commissioned.

COMPETITION

At the discretion of the EG staff, you may be competing against other groups in your section. The winner of the competition will be the team that creates the VI that has the locomotive traverse the shortest distance in its outbound and return trips combined, with all teams using the same arrangement of blocking cars. In the event of a tie, the team with the lowest cost will win.

FINAL PRESENTATION

Your final presentation will be a technical briefing, similar to the milestones, plus a sales presentation explaining why MTA New York City Transit should select your company instead of someone else’s. Please include the following:

  • A description of the problem
  • An overview of your solution
  • A description of your company and why it is qualified to successfully do this job
  • The truth tables you created
  • The resulting logic equations derived and simplified via your K-Map
  • Your final LabVIEW programs
  • The cost estimate
  • Your MS Project from each milestone showing your progress
  • A video of the locomotive traversing the layout from left to right and returning
  • Why your company is the best choice in awarding this contract

After you deliver your final presentation, you will proceed to the model shop to have your work commissioned, if you are not commissioned already. A signed commissioning statement must be included with the TA copy of your final proposal cover letter.

Appendix A: Train Electrical Specifications:

Output control of the track

Train1.gif

Figure 1: Layout of the eight sectors on the train track

Each part of the track is separated into different sectors. The sectors can be classified into two types, X and Y (refer to the diagram). Sectors 1, 4, 5, and 8 are X type and Sectors 2, 3, 6, and 7 are Y type.

There is a Sub-VI that will be provided that will cause the tracks to move depending upon which data is sent to the VI. Only include this Sub-VI in your their logic VI. The Sub-VI has eight inputs which are Boolean named, Sector1 through Sector 8.

For the X type sectors, a Boolean value of True will cause the tracks to be oriented for the train to cross. A Boolean Value of False will cause tracks to be oriented for the train to go straight.

For the Y type sectors, a Boolean value of True will cause the tracks to be oriented for the train to be diverted to the outside track. A Boolean Value of False will cause the tracks to be oriented for the train to be diverted to the inside track.

Input from the track

Train7.gif

Figure 2: Layout of the twelve possible positions of train cars on the train track

There are twelve possible locations for train cars which can be located on positions A to L. A Sub-VI will be provided to you that will have twelve Booleans outputs named Input A through Input L. A True will represent a train car being present and a False will represent a car not being present on that position. These outputs will be used as the inputs to your digital logic circuit.

Appendix B: LabVIEW

On the Front Panel, there must be 12 Boolean switches to represent the 12 inputs of the train and 8 Boolean lights to represent each of the 8 sectors.

  • On the front panel of the LabVIEW program, right click on the connector icon on the top right hand corner icon. Choose Show Connector.
  • Right click on the connector icon and select Patterns. Choose the pattern with 28 nodes.
  • Train8.jpg

    Figure 1. Twenty-eight node pattern

  • To assign the Boolean switches and displays to a node, click on the Boolean switch or light on the front panel then click on the node you wish to assign it to.
  • If you make an error in a connection, right click the incorrect terminal and select Disconnect This Terminal.
  • The 8 nodes on the left side will be for the Boolean switches representing inputs showing occupancy for locations A-H. The 4 nodes on the bottom half of the icon starting from the left will be the inputs for locations I-L.
  • Connect the 8 Boolean outputs that represent the orientation of the sector to the 8 nodes on the right side of the icon.
  • Input
    A

     

     

    No
    Path

    Direction
    of Travel

    Top or
    Bottom

    Reverse
    Running

    Sector
    1

    Input
    B

    Sector
    2

    Input
    C

    Sector
    3

    Input
    D

    Sector
    4

    Input
    E

    Input
    I

    Input
    J

    Input
    K

    Input
    L

     

     

    Sector
    5

    Input
    F

    Sector
    6

    Input
    G

    Sector
    7

    Input
    H

    Sector
    8

    Figure 2: Node assignments of the student’s digital logic circuit

    • Replace the faded icon in the program Official Component Test.vi with your digital logic VI. Right click on the icon and choose replace. Then choose Select a VI and finde your VI. Replace it as shown in Figure 3.
    • Train9.jpg

      Figure 3: The program Official Component Test.VI for students to insert their logic circuit

    • Before testing your digital logic circuit, turn on the power to the middle workbench where the two power supplies are connected.
    • Continuously run the Official Component Test.vi and ensure that the lights on the front panel accurately represent the presence or absence of a train.
    • Flip the Reset switch up and down and the track will be preset to the specified orientation.
    • Once those parameters are checked, test the digital logic circuit by flipping the Test Track switch.


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