Railroad & Co. TrainController Gold
Feedback sensors – occupancy sensors or momentary track contacts
Block – one or more feedback sensors
| Blocks | |
|---|---|
| Down Loop | One way |
| Up Loop | One way |
Momentary Track Contacts Vs. Occupancy Sensors
Momentary track contacts are switched on briefly when a train passes a specific point on the layout, then switch off again as the train clears the contact.
Occupancy sensors are switched on when a train enters a defined track section and stay on until the whole train leaves, provided at least one vehicle in the section draws current (locos do by default, other stock needs resistor wheelsets or lighting).
Slowing Trains to Stop at a Signal
To bring a train smoothly to a halt at a signal, the track is divided into blocks, each monitored by sensors. Within a block, two main control points are used:
- Brake markers: These are positions in the block where a train that is required to stop begins to slow down. The deceleration rate (or braking ramp) can be adjusted so that different trains reduce speed realistically before stopping.
- Stop markers: These are positions in the block where the train actually comes to a stand. Ideally, the stop point is chosen so the whole train fits inside the block and, if relevant, aligns with a platform or signal. In some cases — such as long trains in short loops or sidings — the stop marker may leave part of the train extending into the previous block, provided occupancy is still correctly detected.
If a train is not required to stop, it will pass both brake and stop markers without any change in speed. If no stop marker is defined, the first brake marker in the block becomes the stop point by default.
Markers are linked to track sensors — either occupancy detectors or momentary contacts — so the system knows when a train has reached the braking or stopping point. It is possible to add multiple markers to the same sensor to cater for different train lengths (for example, passenger trains stopping at a platform vs. freight trains waiting at a signal).
Correct calibration of braking is important: if the threshold speed of a train is set too low, it may stall before reaching the stop marker. Brake and stop markers always need to be in the same block, since braking only makes sense if the train is expected to stop before leaving that block.
In practice, brake markers ensure a smooth deceleration, while stop markers determine the precise point where the train halts — usually just before a signal at the end of the block.
Train Length and Blocks
Ideally, a train should fit completely within the block where it is meant to stop. That keeps operation straightforward:
- The block behind clears cleanly when the train has moved on.
- Following trains are protected without complication.
- Stopped trains look realistic, fully inside the signal or alongside the platform.
But this isn’t always essential. In some situations, especially with occupancy sensors, it can be useful for a train to straddle two blocks:
- The rear of the train remains detected in the block behind, so the signalling logic still shows it as occupied.
- Long trains in yards, sidings, or short loops can be handled even if they don’t physically fit in a single block.
The important condition is that all vehicles are reliably detected. If only the locomotive draws current, the rear of the train may be invisible to the system. Adding resistor wheelsets or lighting to unpowered stock ensures that every part of the train is correctly reported.
Slowing Trains to Stop at a Station
Stopping at a station works on the same principles as stopping at a signal, but the emphasis shifts to passenger convenience and train positioning:
- Brake markers: placed far enough in advance that the train has time to slow smoothly before reaching the platform. Different trains may use different braking ramps to reflect their braking performance.
- Stop markers: positioned so the train halts with the doors aligned to the platform. For shorter trains, a marker closer to the middle of the platform may be appropriate; for longer trains, a marker at the platform end may be used.
It is often useful to assign multiple stop markers within the same block. For example:
- A passenger train might stop in the middle of the platform to line up with waiting passengers.
- A freight train routed through the same block might instead draw forward to the signal at the end.
Automation software allows these markers to be limited to specific trains or schedules, so each type stops in the correct place without manual intervention. The same flexibility can also be applied to operational situations — for instance, a train on one schedule might stop at the platform, while the same train on a through schedule passes straight through.
As with signal stops, it is important that the whole train fits within the block whenever possible. If a train is too long for the platform, it may be necessary to define special stop markers that accept overhanging into the previous block, provided reliable occupancy detection is maintained.
Well-calibrated braking curves are essential for station stops, because overshooting looks unrealistic and undershooting can leave doors off the platform. Fine-tuning each train’s threshold speed and braking profile gives smooth, repeatable halts exactly where required.