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Trak-DTL (Track DeTector Latch) - Dallee Electronics

Trak-DTL (Track DeTector Latch)

$34.95
Item Number: #366
  • Automate Reverse Loops
  • Stop Every Other Train at a Station
  • Automate Back-N-Forth Tracks Without Timing
  • Automatic Station Stop After a Number of Unstopped Passes

The Trak-DTL latching model train detector toggles the relay each time current (a train) is detected. This can be used to reverse the polarity of the track, activate or deactivate electronic features, or allow for reverse loops without crossing polarity. Works with DC or DCC.


The Trak-DTL Can Automate

  • Reverse Loops
  • Reversing track polarity for a variable speed automatic back­-n-­forth
  • The control of polarity reverse type switch machines
  • Sequencing i.e. automate station stops so that every other train must stop at the station.

The TRAK-DTL is a variation of current detection (TRAK­DT) that includes a latching circuit to hold the relay position. As a result of this latching circuit, each time current flow is sensed by the detection coil, the TRAK-DTL changes the state of its relay. When current ceases to flow for a few seconds, the TRAK­DTL is then ready for the next sense of current flow to change the state of its relay. This event is repeated again after a few seconds of no current flow occurs.
Current Sensed -> Relay Activates -> Current Removed -> Current Sensed -> Relay Deactivates -> Current Removed -> Reset

The relay has double pole, double throw (DPDT) contacts so it can be wired as a polarity reversing switch. This allows the TRAK-DTL to be used to automate reversing loops. It can also operate DC powered switch machines in conjunction to it's track power control when adding the 555 RELAY BOARD. Reverse loop's are normally broken into 1/3 sections. This way when the engine enters the "sensed section" the relay would immediately reverse but the TRAK­DTL will continue to sense current flow until the entire engine clears the section of track. This way a caboose that has lights with no other cars in the train drawing any current, you would not re­trigger the TRAK­DTL causing a double reverse. It can also be used to provide a continuous "back and forth" operation on a single track such as for a trolley car or engine on a work bench, utilizing DC track power. Drawings utilizing the TRAK­DTL can be found in our Wiring Guide.

The TRAK-DTL can also be used to set up sequential functions by having the relay enable other devices when activated and disable these devices when relaxed. The TRAK­DTL can also be cascaded with each other to perform as many divides of occurrences you would like. This way a trolley / train can pass the station numerous times before it stops. Various other types of items can be made to work in delayed fashion this way as well. A typical way of forcing block or timed stops is to merely turn on a ballast lamp while passing the lamp power through the other detectors sense coils. All kinds of automation and wiring can be done with the TRAK­DT family with simple wiring of the logic you want your trains to do! The RED LED provides for an easy visual indication for activation.


Power Requirements

All Dallee current detectors require a regulated 12 volt DC power supply. We recommend the 12VPS to power up to five detectors. Please use a regulated source as unregulated power can destroy the electronics on board.


Terminal Overview

Relay Not Activated

Model Train Block Occupancy Detector Relaxed
When the relay is not activated, the right and middle contacts are connected and the left most connector is connected to nothing.

Relay Activated

Model Train Block Occupancy Detector Activated
When the relay is activated, the left and middle contacts are connected and the right contact is connected to nothing.


Terminal Overview

  1. Decide on a section of track which will trigger the detector. Isolate one rail (either rail on two rail, center for three rail) for the length of the section of track by adding a small gap in the rail.
  2. Route a new power lead for that section of track, passing it through the sense coil on the Trak-DTL board.
  3. Connect the power leads to the Trak-DTL. At this point the detector is ready to use.
  4. For more detailed wiring guides, please reference the Dallee Wiring Guides.
Trak-DTL Basic Installation Instructions


Technical Specifications

Item Number 366
Instructions Trak-DTL Latching Current Occupancy Detector Timer #366 Full Instructions
Other Uses and Operations (See Wiring Guide)
Relay Style Double Pole Double Throw (DPDT)
Relay Current Handling 5 Amps
Power Input (For Electronics on Detector Board) 12 Volts Regulated DC



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