|
|
|
|
|
How to configure a crossing signal system for your model railway
|
|
To help you choose the right number of train detectors and crossing signal controllers, find the configuration that best represents your grade crossing on your layout.
• One track, trains travel in one direction
• One track, one direction with station stop near the crossing
• One track, trains travel in both directions
• One track, both directions with station stop near the crossing
• One track, crossings close to each other (shared detectors)
• Two or more tracks at the crossing
|
One track, one direction, very basic
This is a single track crossing. Trains travel in one direction, in this case from left to right.
When detector FW senses a train, the controller will turn on the signals. When the end of the train clears detector FW, the controller will keep the signals flashing for 28 seconds, then turn them off.
|
The following modules are required for this installation:
• One MRX1 controller
• One MRD1 single detector
|
|
One track, one direction, more realistic
Adding a second detector at the far side of the road allows more prototypical operation. The signals will turn off as soon as the train clears the crossing.
When detector FW senses a train, the controller will turn on the signals. The train has up to 28 seconds to reach detector NE. As long as detector NE senses a train, the signals will flash. When the end of the train clears NE, the controller will turn off the signals.
|
The following modules are required for this installation:
• One MRX1 controller
• Two MRD1 single detectors
|
|
One track, one direction, with station near the crossing
Trains travel in one direction, in this case from left to right.
Local trains stop at the station, express trains do not.
When detector FW senses a train, the controller will turn on the signals. When the end of an express train clears NE, the controller will turn off the signals.
When a local train approaches the station and triggers detector FW, the controller will turn on the signals. The local stops at the station and the controller will turn off the signals 28 seconds after FW was first triggered. The signals will turn off even if the rear of the local train is parked on detector FW.
As the local train departs the station it will trigger detector MW. The controller will restart the signals. The train has 28 seconds to reach detector NE. As long as NE senses a train, the signals will flash. As soon as the train clears NE, the controller will turn off the signals.
|
The following modules are required for this installation:
• One MRX1 controller
• Three MRD1 single detectors
|
One track, trains travel in both directions:
|
One track, two directions, very basic
This is a single track crossing. Trains travel in either direction.
When an approaching train triggers either detector, the controller turns on the signals. As long as the detector is sensing a train, the signals will flash.
When the train clears the first detector, the signals will operate for up to 36 seconds, giving the train time to reach the opposite detector. The signals will continue flashing until the train has cleared both detectors.
|
The following modules are required for this installation:
• One MRX1 controller
• Two MRD1 single detectors
|
|
One track, two directions, more realistic
Adding detectors at both sides of the road allows more prototypical operation. The signals will turn off as soon as the train clears the crossing.
When detector FW senses a train, the controller will turn on the signals. The train has up to 28 seconds to reach detector NW. As long as detector NW or NE senses a train, the signals will flash. When the end of the train clears NE, the controller will turn off the signals.
Similar operation happens for westbound trains.
|
The following modules are required for this installation:
• One MRX1 controller
• Four MRD1 single detectors
-- or --
• One MRX1 controller
• One MRD6 HexDetex detector
|
|
One track, both directions, with stops near the crossing
Trains travel in both directions. Trains might stop at the station or semaphore.
When detector FW senses an eastbound train, the controller will turn on the signals. When an express train which does not stop at the station clears NE, the controller will turn off the signals.
When a local train approaches the station and triggers detector FW, the controller will turn on the signals. The local stops at the station and the controller will turn off the signals 28 seconds after FW was first triggered. The signals will turn off even if the rear of the train is parked on detector FW.
As the local train departs the station it will trigger detector MW. The controller will restart the signals. The train has 28 seconds to reach detector NW. As long as NW or NE senses a train, the signals will continue flashing. As soon as the train clears NE, the controller will turn off the signals.
|
Similar operation happens for westbound trains, which may or may not stop at the semaphore.
(The semaphore is not part of the crossing signal system.)
The following modules are required for this installation:
• One MRX1 controller
• Five or six MRD1 single detectors
-- or --
• One MRX1 controller
• One MRD6 HexDetex detector
|
Crossings adjacent to each other, shared detectors:
|
One track, road crossings near each other
Each set of crossing signals needs its own controller. The two controllers can share detectors as shown in this example.
Detector A gives early warning of eastbound trains approaching the 1st Street crossing . Detector C gives early warning of eastbound trains to 2nd Street crossing, and it also tells the 1st Street crossing when the train has cleared 1st Street.
When one detector connects to two or more controllers, make sure the QC 'common' terminal on the detector is wired to C on all the controllers.
|
The following modules are required for this installation:
• Two MRX1 controllers
• Six MRD1 single detectors
-- or --
• Two MRX1 controllers
• One MRD6 HexDetex detector
|
Two or more tracks at the crossing:
|
Two tracks, two directions, very basic
This is a multi-track crossing. Trains travel in either direction.
In this example, the detector on the west side consists of two detector modules, A and B embedded in the roadbed. They are wired in parallel.
On the east side, detector C is a single module set up to sense across both tracks. You may use either configuration for the west and east detectors.
When an approaching train triggers a detector, the controller turns on the signals. As long as any detector is sensing a train, the signals will continue flashing.
When the train clears the first detector, the signals will stay on for up to 36 seconds, giving the train time to reach the opposite detector. The signals flash until the train has cleared both detectors.
|
The following modules are required for this installation:
• One MRX1 controller
• Two, three or four MRD1 single detectors
-- or --
• One MRX1 controller
• One MRD6 HexDetex detector
|
|
Two tracks, single directions
For this double-track crossing, trains travel in one direction on each track.
In this example, traffic moves from right to left (east to west) on Track 1 and from left to right (west to east) on Track 2.
An approaching train on Track 1 will trigger detector FE. The signals will start flashing. The train has 36 seconds to reach detector NW, or the signals will reset. The signals will continue to flash as long as the train is on detector NW. They will turn off when NW is cleared.
Similar operation occurs for trains approaching from the west on Track 2.
|
The following modules are required for this installation:
• One MRX1 controller
• Four MRD1 single detectors
-- or --
• One MRX1 controller
• One MRD6 HexDetex detector
|
The basic multi-track configuration shown above provides reasonable performance for straight-through mainline operation. If train length is shorter than the distance between detectors, and if trains stop while between the detectors, then there may be times when a train is blocking the crossing but the signals are not operating.
For more prototypical multi-track operation, each track should have its own detectors and its own controller.
- Use the single track examples above to place the detectors on each track.
- Connect the signals to Track 1's MRX1 controller.
- All other controllers connect to Track 1's controller to trigger the signals.
- Tracks 2, 3, 4, etc. may use MRXP parallel controllers to save cost.
See the controller installation instructions (pdf) for detailed wiring info.
|
[Back to the top]
© copyright 2009-2011 Azatrax, Longmont, Colorado
|
|
