TrainSpeed is a train performance calculator to simulate the performance of a train running over a particular route.
TrainSpeed calculates the running time over a given route using a given train. You may select from any route data file and from any train data file on disk. You may edit the route or train performance data, you may simulate the run calling at all stations, selected stations or non-stop.
A simulator attempts to emulate the behaviour of real events in a virtual setting. In this context, the speeds and running times attainable by a real or proposed train over a complete or partial route can be calculated on a computer. The purpose of doing this is to derive running times for the trains so that a working timetable for the route can be compiled.
TrainSpeed also allows comparisons to be made very easily and quickly between different options such as:
The TrainSpeed program works by taking the various characteristics of the route and the train running on it and deriving the possible and permissible speeds. It then “drives” the train over the route.
Every second, TrainSpeed calculates the train’s current speed and compares it with the permissible speed. It also looks ahead for the next applicable speed restriction or stopping point. The program then decides whether the train should accelerate, decelerate or maintain its current speed. It then calculates the distance run over the next second and the speed at the end of that time.
TrainSpeed makes assumptions on driving style which can be selected by the user. A “normal” driving style makes use of maximum available power and adhesion, whilst a “defensive” driving style restricts tractive effort and braking rates to lower values. The latter is useful for checking performance and running times during the leaf-fall season, for example.
External environmental factors such as strong winds and low temperatures are not accounted for by TrainSpeed. These can both adversely affect performance in extreme conditions.
TrainSpeed has been written primarily to suit the UK railways using miles and chains for locations and miles per hour for speeds. The current version is unsuitable for railways using metric units for speed and distance.
Route characteristics are held in a route data file. Details are in miles and chains for station locations, start and end points of curves, and changes in gradients. Station dwell times are given in seconds, speeds in miles per hour and curve radii in metres. TrainSpeed can accept a route with either increasing or decreasing mileage but cannot cope with a break in mileage. This can happen at a junction where the line mileage has a different origin and may even run in the opposite direction.
Train performance characteristics are held in a train data file. The following values are used: maximum speed, maximum power, motor efficiency, tractive effort, auxiliaries (hotel) power demand, brake force (for loco-hauled trains), total mass, rotating masses, passenger load, length, height, width, and factors for aerodynamic drag and rolling resistance.
Tractive effort is used to calculate accelerations at lower speeds before the aerodynamic and other effects become significant. Both maximum and continuous values are needed, together with the speed at which the change between the two becomes effective.
Modern passenger multiple-unit rolling stock is fitted with a three-step brake where nominal brake rates are set at 3%g, 6%g, and 9%g for brake steps 1, 2, and 3 respectively. Loco-hauled trains have different braking curves, the current release uses a value of total brake force for the whole train.
Whilst running the simulation, TrainSpeed will present a graph of speed against distance showing current progress. This shows the distance in miles and chains as defined in the current route against the speed attained by the train. The station locations are set out along the distance axis, the PSR profile is shown in black, the gradient profile in green, and the train’s actual speed is plotted in red. At the same time, TrainSpeed writes a file to disk giving the following information:
The file is in comma delimited text format with a header row and can therefore be directly imported into any spreadsheet for further graphing and presentation to suit your preferences.
The software setup file installs the program by default in a new TrainSpeed directory under your Program Files and a selection of data files are installed in a new TrainSpeed directory under your Documents folder. The simulation output .csv files are also placed there. If you choose to uninstall the program, only the program and menu items will be removed, the TrainSpeed Documents directory and its contents will not be affected.
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Click to download the Help file, I suggest you opt to save the file first and then open it to read. The TrainSpeed software is currently undergoing a comprehensive upgrade and will be available after final testing. |
Updated March 2010 © J S Rastall |