SAS2-BR DC Model Railway Shuttle Controller with Station Stops

About the Product

The BLOCKsignalling SAS2-BR is an automatic DC model railway shuttle controller with station stops and built-in speed control, designed to operate a single locomotive backwards and forwards with realistic acceleration and deceleration. It can also provide one or more intermediate station stops for more realistic automatic train operation.

When the locomotive reaches an isolated section at the end of the line, the SAS2-BR detects the train and automatically decelerates it to a standstill, waits for the selected period and then accelerates it away in the opposite direction. The process repeats at the other end, providing continuous automatic shuttle operation without requiring a separate DC speed controller.

One or more intermediate station stops can also be added. As the locomotive enters a station section, it automatically slows to a stop, waits for the selected period and then accelerates away in the same direction. There is no fixed limit on the number of intermediate station sections that can be used along the shuttle line.

The SAS2-BR includes on-board speed and waiting-time adjustments, together with programmable settings for acceleration, deceleration, individual stop durations and fixed or randomised delays.

Key Features

• Automatically operates a single DC locomotive backwards and forwards.
• Supports one or more intermediate automatic station stops.
• Can also operate a train continuously around a loop with station stops.
• Built-in DC throttle removes the need for a separate speed controller.
• Smooth acceleration and deceleration for realistic train movement.
• Adjustable locomotive speed using an on-board control.
• Adjustable waiting times at the ends of the shuttle and at station stops.
• Programmable acceleration and deceleration rates.
• Fixed or randomised waiting times for more varied operation.
• Uses isolated track sections for automatic train detection.
• Suitable for OO/HO and smaller locomotives.
• Maximum traction current of 0.5A.
• Emergency stop function using the on-board push button.
• Built-in short-circuit protection.
• Can also be triggered using reed switches, push buttons or other suitable devices.

The SAS2-BR is a self-contained DC throttle, so a separate train speed controller is not required. The locomotive's top speed is set directly using the SPEED adjustment on the module, while additional programmable settings allow the automatic operation to be tailored to the layout.

Basic DC Shuttle Operation

For basic shuttle operation, the track is divided into a main section and two isolated end sections. When the locomotive enters an end section, the SAS2-BR detects it and begins the automatic stopping and reversing sequence. The end sections should be long enough for the locomotive to be detected and come to a complete stop.

DC Shuttle with Station Stop

Additional isolated sections can be created for automatic station stops. These should extend sufficiently either side of the platform to allow the locomotive time to decelerate. Any number of station sections can be used, with each connected to the S terminal.

Loop Operation with Station Stop

The SAS2-BR can also operate a locomotive continuously around a model railway loop with an automatic station stop. The locomotive travels forwards around the loop, stopping at the station for the programmed delay before continuing around the layout.

Speed and Waiting Time Adjustment

The on-board SPEED adjustment controls the locomotive's maximum speed. Waiting times can also be adjusted, with additional programming available to set individual end and station waiting times.

Programmable Operation

The SAS2-BR provides additional programming options for customers who want greater control over the automatic sequence. Acceleration and deceleration can each be adjusted between 1 and 20 seconds, while waiting times at the ends of the shuttle and at station stops can be individually configured.

Waiting periods can also be set to fixed or randomised operation. When randomised, the actual delay varies between approximately 25% and 100% of the programmed waiting time, helping make repeated automatic operation appear less predictable.

Electrical Requirements

• Supply voltage: 12V DC
• Recommended power supply: Minimum 0.5A for Z/N gauge; 1A for OO/HO
• Maximum traction current: 0.5A
• Power connection: Screw terminals or DC power jack
• DC jack size: 2.1mm
• DC jack polarity: Centre positive
• Layout suitability: OO/HO and smaller locomotives

The module should be powered using a suitable 12V DC power supply. A compatible BLOCKsignalling PSU2 12V DC 1A Power Supply can be used. Do not power the SAS2-BR from the auxiliary terminals of a train controller, as these outputs may not provide sufficiently smooth or stable power.

Protection & Emergency Stop

The SAS2-BR includes short-circuit protection. Pressing the on-board push button also immediately removes track power, providing an emergency stop for re-railing, changing a locomotive or stopping the train when necessary.

Documentation & Support

For full installation instructions, wiring, programming options and troubleshooting, please refer to the product instruction manual:

Product Instruction Manual