User:Davidmichael47/enes100/fall2013/p1Modelrailroad504

Problem Statement (Finish description)
Railroads sort cars according to their destination in classification yards. Although the arrangement of the tracks in a yard may be complex, each track has a definite purpose.

Two types of classification yards are used. Larger yards are gravity yards. Cars roll down a hill. The track the cars are on fans out into a set of tracks. Cars with the same destination are routed to the same track. Gravity Yard

Smaller classification yards are are flat switching yards. A small locomotive pulls cars from the arrival track and shunts them to a classification track according to their destination. Flat Switching

The objective of this project is to model a small flat switching yard. Cars will be sorted according to their imagined destination. Two modules modeling a small flat witching yard have been donated to the Engineering Department. An ultimate goal of the project is to automate operation of the model so that it can be set up as a display and operate hands-off to promote Engineering.

Conceive
Market/Customer Needs The customer is the Engineering Department. The need is to promote and stimulate interest in Engineering.

Initial target goals Build an operational track. For the first stage, the goal is to make the model operational by manual, i.e. hands on, means.
 * 1) Document the two modules, including a measured scale drawing of the track arrangement and an electrical diagram showing the wiring of the track, and the location of current isolating gaps.
 * 2) Document the wiring of the switch motors.  It is desired that only a single button be pushed to select a route.
 * 3) Repair track work, as necessary.
 * 4) Complete the wiring of the power feeders from the power supply to the track.
 * 5) Wire the switch motors.  The switch motors should be wired so that a route can be selected with a single electrical switch.
 * 6) Standardize the length of the track pieces to cross the gap between the two modules.  Fabricate the "jumper" tracks.
 * 7) Design a control panel
 * 8) Fabricate the control panel and wire it to the railroad.  Electrical connections between the model and the the control panel to be effected without soldering.

System performance metrics
 * 1) Trains operate smoothly at slow speeds (5--10 scale MPH) without frequent derailments.
 * 2) Switch motors operate reliably.
 * 3) Cars can be coupled and decoupled without touching them.

Project cost and schedule Since most of the equipment is donated, can be fabricated, or is readily available, the estimated cost to have the model train tracks operational would be less than $20.00 plus the cost of any unforeseen repairs (i.e. switch motors not working).

Alternatives No alternatives have been discussed yet.

Design

 * Reverse Engineering:
 * Operations Manuals found
 * Tortoise Slow Motion Switch Machine
 * Do not use more than 12 volts.
 * Understanding Kadee Couplers
 * Training video and tutorials found
 * Helpful Hints for Operating Model Railroads
 * Wiring Diagrams
 * Wiring - A How To Guide
 * Locomotive operation
 * DC current passes through the wires into into several places among the track for electrical distribution. If it only attached to the tracks at one point each, resistance would build further along the track and cause the train to be noticeably slower. This electricity is passed through the metal frame on the wheels, from one rail to the other, and is connected to a DC motor. The turning of the motor operates on a gear system, causing the wheels to turn along with it, in the desired direction. When the current is switched, the wheels will turn in the opposite direction because of this. DC motors
 * Double Slip Switch
 * Service Manuals found
 * Electrical Handbook for Model RailRoads Vol. 1 by Paul Mallery
 * Theory of Operation
 * The locomotive gets power through the wheels coming in contact with the powered rails. The rails of Module A were already wired, but Module B rails were not completely wired. The team was able to connect all of Module A together to power it up with one power supply. We were also able to solder the wires for Module B tracks, but did not solder it to the tracks themselves.
 * In order for the switches to work properly and not short circuit the track, gaps are required to isolate voltages, as shown in this picture. Switch_wiring.png
 * The break down into assemblies and modules
 * There are two modules for the model train track. The left module for the train tracks is pictured in the following scale diagram (note that the switches are designated as 2a, 2b, etc.):LeftModule.png
 * The right module is pictured in the following diagram:RightModule.png
 * Wiring diagrams (not to scale) are as follows:Track wires A.png

Implementation

 * Test and analysis procedures
 * Will King was able to test the Kadee Couplers. His writeup can be found here.
 * The verification of performance to system requirements
 * Jovy Batong was able to verify which tracks are wired. Her writeup can be found here.
 * The validation of performance to customer needs
 * Sourcing, partnering, and supply chains
 * Possible implementation process improvements
 * Because the team did not know much about electrical theory, most of the time was spent learning that, soldering, and model railroads work. More time is required to complete wiring the railroad. Additional time is required to ensure that the rails are gapped correctly and wiring the switches.

Operation

 * Maintenance and logistics
 * Lifecycle performance and reliability
 * Lifecycle value and costs
 * Pre-planned product improvement
 * Improvements based on needs observed in operation
 * Definition of the end of useful life
 * Disposal options

Next Steps
Research Tortoise Track Switches. Complete wiring diagram. Complete wiring of module. Make bridges for modules.