Stageing Track Control
(from Dick Bronson at R-R CirKits)
At the end of each storage track, the last 15 inches have a separate block with a detector for each track. When the detector first fires, it will trigger a logix which sends an inactive or off command to the track power relay. This provides we an easy way to link the power off to the detection of a train. Resistive wheel sets or engines and current detectors (BOD-8) assure that trains can pull, or back, into the storage tracks.
The power must be cut to the entire storage block, not just a small section at the end to allow multi-unit engines to stop properly. Power is maintained on all units until the train reaches the stopping point. It is then removed from all the units at the same time.
One problem is that simply removing all power would disable current detection and there would be no more indication that the storage track was occupied. Simply adding a 10K resistor, as indicated by Dick Bronson, across the relay contacts assures that sufficient current flows to maintain block detection.
The advantage of using the TC-64 for this operation is that it allows the operation to be event driven. It opens the relay as the detector becomes occupied. However it does not prevent the relay from being closed again to pull the train out of the storage track, even while the end of track detection shows occupied.
When a track is selected, the replay is powered by an active or on status for the sensor and the track power is turned on - for that track only. The relay drivers are placed in a sensor group so that only one is allowed on at a time.
We use the same basic circuit used for local turnout control. The sensor is set to output (custom) with port to Type 'Driver'. The input from the BOD-8 is set to input and the port to be 'Detector'.
The track power control Relays are connected as designed by Dick Bronson as shown below. Use only the specified relay which is a special low current relay that may be driven directly from a TC-64 output port. Only one of 8 possible relays is shown in this diagram.
K1 Relay TX2SA-5V
D1 Diode 1N4148
R1 10K ohm
We have developed what we call the Bronson Track Control Card
The card is connected to the plant wires as follows:
Blue is a blue or +5 volt line and inputs 1-5 are the green wires sensors to control the five relays on the card. The Outut side has a Black wire to the zone Master Main bus and the Yellow lines 1-5 are to the tracks controlled by the card. Each of these connections has two wire attached. One goes directly to the length of the staging track and the other goes to the last 15 inches with has a detector attached. The detectors go to a BOD-8 to indicate occupancy.