CE 353 Laboratory Week 3: Queueing and Delay at a Railroad Crossing

The objectives of this lab are:

To provide a real-world example of queueing and delay studies.
To familiarize students with types of railroad cars.

Initial Instructions

Get a new partner (i.e., one that you haven't had before) - for this lab this shouldn't be a problem!
Work in teams of 2
Submit only one report for the entire team
Submit only one Word file and only one Excel file for the entire team

Problem Description:

We will be counting vehicles and train compositions at the intersection of the Union Pacific line and Dayton Ave. in East Ames. Print out the data sheets or create your own. Review the railcar classification types at the end of this page as well.

For each hour time slot, one person should observe northbound traffic and one should observe southbound traffic. The northbound observer should be on the north side of the tracks along Dayton Ave. and the southbound observer should be on the south side of the tracks along Dayton Ave.

Each person should select an arbitrary point along Dayton Ave. on their side of the tracks at which they will observe the vehicles on Dayton Ave. as they pass. This location should be reasonably close to the tracks but not so close as to endanger oneself from flying rocks, etc.

As vehicles pass this point, record the times they do so to the second (as illustrated in the sample below).

When a train comes, record the time at which the train inhibits traffic (i.e., when the crossing signals activate) and begin to count the types of cars by classification. When the train passes (i.e., when the crossing signals stop and traffic begins to move again), record this time as well and begin to record vehicle times once again. (This is shown in the sample below).

Safety Notes:

Park well away from the Union Pacific tracks and Dayton Ave.
Stay clear of the tracks for obvious reasons as well as the facts that trains can "throw" stones and such.
Observe from a safe vantage point.
SAFETY IS YOUR FIRST CONSIDERATION!!!

Tasks:

Collect data on traffic and train composition (you may use these Data Sheets).
Submit a report using the Lab Report Template and the Sample Excel File. Within the Lab Report, you must:

Enter the data into an Excel file and use this to draw a Queueing Diagram using your data (Use the Excel File, either the example on the Queueing Diagram worksheet or the Alternative worksheet, not both (note in your report which you used). [Directions for use]).
Estimate total delay and total length of queue using the Queueing Diagram. Report this in the Lab Report Template.
Within the Lab Report Template, comment on the experience of collecting data. Was it difficult? Were there ways in which it might have been done better? If so, comment on how it might have been done better. Were there circumstances/situations which made it more difficult? Were the results of the data collection the ideal ones for creating the queueing diagram and estimating total delay and total length of queue?
Include in your report your collection of train composition. Note any difficulties or confusion as per above.
Submit your Word file (the report) and your Excel file (the data and queueing diagram) per the Lab Report Submittal Instructions.

Directions for Using the Excel File

After downloading the Excel file (i.e., diagram.xls), open it and note at the bottom that there are two Excel Worksheets available: Queueing Diagram and Alternative. The difference between these is the method of inputting the data and the resulting queueing diagrams.

For either worksheet, you must indicate the times for which you collected data and the direction of travel you were gathering data for.

For the Queueing Diagram worksheet, simply enter the time (in seconds) from the beginning of your data collection period (e.g., 8:00am) when each car passed the arbitrarily chosen point into the "Time (sec.)" column. Once done with that, copy the second entry of the Cum # Vehicles column from that point until the end of your vehicle times. This column should then have numbers increasing from 1 to the total number of vehicles passing during your data collection period. Then, change the graph's Source Data to reflect the size of your data entry fields (Click with the right mouse button when the mouse pointer is over the graph, select Source Data, and enter the appropriate Excel field sizes.) This method results in a discrete-looking graph.

For the Alternative worksheet, enter a one under the "Vehicles" column at each time (in seconds) from the beginning of your data collection period (e.g., 8:00am) when each car passed the arbitrarily chosen point. You may have to lengthen the "Time (sec.)" column to accommodate your data. Do this by choosing the last entry in the "Time (sec.)" column, copying it, and pasting it to the length of time required. Once the "Vehicles" column has all of its data, copy the last entry in the "Cum # Vehicles" column as you did for the "Time (sec.)" column. Then, adjust the graph's source data as mentioned for the Queueing Diagram worksheet. This method results in a more continuous-looking graph.

Assigned Times for data collection.

Data Sheets:

Vehicle counting sheet:

This sheet has space for 296 vehicles; therefore, if you use this sheet you might print multiple copies. Click here to view sample on a page by itself which facilitates printing.

Sample:

The first vehicle on this data sheet passed at 8:53:16, the next at 8:53:18, the next at 8:53:36, and so on. You must only indicate the hour and minutes once per minute (or just the minutes once if you specify the hour on your data sheet somewhere). A train inhibited traffic at 8:54:40 until, roughly, 8:56:02 (the precise end time is shown on the train counting sheet).

Train counting sheet:

Click here to view sample on a page by itself which facilitates printing.

Sample:

The first train on this sheet began inhibiting traffic at 8:53:40 and stopped doing so at 8:56:00. There were 3 locomotives (as shown by the tick marks), 10 box cars, and so on. You may extend each train's data collection to additional rows if the number of cars warrant. You may also use the standard 4 marks and a slash notation to denote 5 cars.

Railroad Car Classification Guide:

(Sources are Norfolk Southern Terms (most of the terms) and Union Pacific Rolling Stock Descriptions (the photos and some terms))

Boxcar: an enclosed car used for general service and especially for lading which must be protected from weather.

Flatcar: an open car without sides or roof.

Piggyback Flatcar: a type of flat car specially designed to ship trailers or containers.

Gondola: a freight car with sides but without a roof.

Open Top Hopper: an open-top car with pockets, or hoppers, opening on the underside of the car for unloading bulk commodities.

Covered Hopper: The covered hopper has a permanent roof with round hatches or a trough to facilitate the customer's loading requirements.

Multilevel (or AutoRack) car: a long flatcar designed with one or more deck levels in addition to the car's main deck; used to haul new automobiles and trucks.

Tank car: used to ship compressed or liquid commodities, the majority of tank cars are owned by non-railroad companies.