The “circle†is a set of joined rail tracks
A Circle Train runs on a continuos joined fast rail track. Therefore fast tracks are joined to a continuos line where trains run withouth stop. The start and stop at the destinations happens outside of the circle, thus trains enter and leave the circle through joins.
The simulation based on the circle is a simplification, to make the system easier to understand and calculate. In addition, the circle represents the maximal potential that could be reached by a continuos track.
In the ideal case, this is a circle. In the real world, this will be any form of joined high speed tracks.
A continuos track does not demand a complete new build, it only needs a bypass around cities and densely populated areas where tracks pass train stations or have to be run with reduced speed because of savety reasons. This is an important detail as it reduces the installation costs about 90% compared to a other transport system (like magnetic monorail) where the complete infrastructure has to be build and financed – and cannot used by conventional trains anymore. Only the fraction of those bypasses have to be built, the rest of the infrastructure can be reused – including the trains, coaches and waggons.
Constant speed on the circle
The Circle Train must run on the circle track with a constant speed to optimise the troughput. That is, it must enter and exit the circle with that speed and it will never change that speed during the travel on the circle (except in case of an emergency).
Apart from increasing the througput (because there is no slowdown of the whole system) there is a great advantage from this premise for security ( it is much easier to predict where a train will be at a certain time) and also for the energy balance, see the verbose description below.
The constant speed can only be achieved if train stations are circumnavigated. That means the fast tracks have to be joined through bypasses, that have to be build around big cities.
Trains start and stop only outside of the circle
All trains start outside of the circle on a “regular†track, passing train stations to start and stop with all its acceleration and deceleration.
To reach the final destination, the trains must leave the circle.
In the first version of the simulation, trains are always running from only 1 start destination to 1 stop destination.
In a later phase of the study there will be an enhancement: The trains entering the circle can hook and decouple to each other in order to save energy and improve the capacity of the system.
A more verbose description
Today, rails always start and end on train station. During the ride, train stop at train stations the rails run through. Every stop reduces the capacity of the system, and every start-and-stop event needs a lot of energy.
In this circle train system, the train stops only at the beginning and the end of the travel.
The long distance traffic is bypassing the cities running on a closed line. This might increase the throughput because of the constantly high speed and might reduce the energy consumption, because there is only the initial start end the final stop event.
Some details might clarify the setup:
The Tracks of the trains are connected to a closed line, in the simplest form a circle. The track has connection points, where trains from outside of the circle can join into the circle track, or leave the circle track towards the destination.
When trains are approaching the destination, they will leave the circle and slow down to the destination on the track between. or they speed up from the start point to the connection point, where they must reach and keep the constant speed of the circle.
This can be compared to a highway around a city like the peripherique in Paris.
The difference is that only trains capable to keep the speed on the circle are allowed to run on the circle. As the vehicles are trains they are not acting as one thinks best like motor vehicles, but are controlled and guided from a central control point.
Therefore it is possible to run all trains on the circle at a constant speed. This allows to calculate the exact entrance and leave of the trains on the circle as well as the exact position during their journey.
It therefore is possible to calculate and predict the slots available between the trains and stuff in additional trains if there is enough space (with the necessary safety distance between the trains ). This is exactly what this simulation is doing.