L1-DC Automatic DC Model Railway Passing Loop Controller

About the Product

The BLOCKsignalling L1-DC is an automatic DC model railway passing loop controller designed to operate two trains around a continuous loop with a passing section. When one train arrives at the passing loop, the controller automatically holds it while switching the points and dispatching the other train after a configurable delay.

Two infra-red sensors detect the trains as they enter the passing loop, while isolated track sections automatically stop and release each train. The L1-DC also controls the point motors, allowing two trains to alternate automatically around the layout with minimal operator input.

A range of programmable settings allows the operation to be customised, including departure delays, timed or random operation, push-button departure, sensor sensitivity and train routing behaviour.

Key Features

• Automatically controls two trains around a continuous loop with a passing loop.
• Automatically holds and dispatches trains in sequence.
• Operates the points to route trains onto the appropriate track.
• Controls isolated track sections to automatically stop and release trains.
• Includes two infra-red sensors for automatic train detection.
• Adjustable departure delay.
• Supports timed, random or push-button train departure.
• Programmable regular or random train routing behaviour.
• Adjustable infra-red sensor sensitivity.
• Optional control-panel LED indication.
• Allows normal manual layout operation when the module is switched off.
• Compatible with conventional 3-wire point motors.
• KATO points can be operated using the BLOCKsignalling K-ADAPT.
• Requires a regulated 12V DC power supply.
  

How the Passing Loop Works

Each line of the passing loop contains an isolated stopping section. The two supplied infra-red sensors are positioned before these sections so that an approaching train can be detected before it reaches the unpowered track.

When a train arrives, it passes over the appropriate sensor and comes to a stop in the isolated section. After the programmed delay, the L1-DC changes the points to the other track and energises its isolated section, allowing the waiting train to depart.

Once that train completes the main loop and returns, it is stopped automatically and the sequence can begin again with the other train.

Infra-Red Train Detection

Two infra-red sensors are used to detect the trains automatically. They are normally installed underneath the track, with the invisible infra-red light reflected from the underside of the locomotive or rolling stock.

The sensors can be installed through an 8mm hole in the baseboard and have a detection range of approximately 25mm at the default sensitivity setting, depending on the reflectivity of the vehicle. The optical elements are approximately 2.2mm in diameter, allowing them to see between the sleepers even on smaller scales.

Programmable Operation

The L1-DC provides a range of programmable options so its behaviour can be adapted to different layouts.

The departure delay is 10 seconds by default and can be adjusted up to 255 seconds. Departure can be triggered after the programmed time, after a randomised delay, or manually using a push button.

Train routing can also be configured to follow a regular pattern or use random selection, allowing more varied automatic operation.

Manual Operation

The isolated-section relay contacts are normally closed when power is removed from the L1-DC. This means that when the module is switched off, the isolated sections are reconnected and the layout can be operated manually.

Optional Panel Indicators

Two external LEDs can be connected to provide additional indication on a control panel. By default, these indicate when a train is detected by Sensor 1 or Sensor 2 and flash while a train is departing.

The necessary LED resistors are already incorporated into the module.

Power Requirements

• Supply voltage: 12V DC regulated.
• Typical module current: Approximately 50mA with all panel LEDs illuminated.
• Recommended power supply: 0.25A to 1A.
• Recommended supply type: Regulated plug-top DC power supply.

The module should not be powered from the auxiliary accessory terminals of a train controller, as these may not provide sufficiently smooth or stable power.

Point Motor Compatibility

The L1-DC provides connections for conventional 3-wire point motors, allowing the controller to automatically change the points as trains arrive and depart from the passing loop.

KATO 2-wire points can also be operated by adding the BLOCKsignalling K-ADAPT, which converts the L1-DC's 3-wire point output to the 2-wire connection required by KATO points.

Documentation & Support

For detailed installation instructions, wiring diagrams, programming options and troubleshooting guidance, please download the latest instruction manual:

Product Instruction Manual