Bridge control equipment for a direct-reversing two-stroke diesel engine accomplishes the following procedures:

The bridge control system has a direction selector (ahead/astern lever or a combined telegraph/control lever). When the officer on the bridge selects the required direction (ahead or astern), the control system:

1. Checks the engine is stopped (or at a safe speed) and that the direction interlock is satisfied (the engine must not be running in the opposite direction).
2. Sends a signal to the engine control system which operates the reversing mechanism - on a camshaft engine this axially shifts the camshaft (or rotates the cam) to bring the correct (ahead or astern) cam profiles into line; on a camshaftless engine the ECU switches the injection/valve timing and firing order.
3. The control system confirms the direction change is complete (via position sensors/interlocks) before allowing starting.
4. The direction is indicated on the bridge and in the ECR, and the telegraph records the order.

The direction of rotation is thus set by the bridge lever, with the control system performing the mechanical/electronic reversal and interlocking to prevent starting in the wrong direction.

When the bridge lever is moved to the "start" position (or the start button is pressed), the control system:

1. Checks the interlocks (turning gear disengaged, direction set, starting air pressure available, no alarms).
2. Opens the main starting air valve and operates the air distributor to admit starting air to the cylinders in the correct order, turning the engine.
3. When the engine reaches a set speed (e.g. a few rpm) and the direction is confirmed, the control system cuts off the starting air and admits fuel (injection begins) so the engine fires and accelerates.
4. The governor then takes over to control the speed to the set value.

The bridge control thus sequences the start automatically, with the engine accelerating to the commanded speed.

The bridge lever (or a separate speed control) sets the desired engine speed. The control system:

1. Sends the speed set-point to the governor (electronic or electro-hydraulic).
2. The governor adjusts the fuel injection (fuel pump index) to bring the engine to the set speed, with a controlled rate of change (acceleration/deceleration limits) to avoid overloading or thermal stress.
3. The speed is maintained by the governor against load changes.
4. The bridge control includes load limits (e.g. maximum fuel index, torque limit) to protect the engine, and the speed is indicated on the bridge.

The bridge control thus provides remote, automatic control of engine speed through the governor, with the necessary protection.