Cab Control is a term used for Direct Current (analog) power management. The throttles are referred to as cabs.
During operation, electrical switches are used to route power to blocks. The Digital Command Control equivalent is a power district. The switch controlled which cab was connected to its block. More complexity meant more switches (and wiring) to connect the cabs to the track.
During operation, the operator would set the switches to connect/disconnect his cab to the block. As the train progressed down the track, the cab would be connected to the blocks needed, and the operator would disconnect his cab from those blocks he had left. If a train entered a block with no assigned cab, it would stop. If the block were assigned to another cab, the operator would lose control of his train.
For a large layout, someone may be assigned to the Dispatcher job, having control of all turnouts, signals and blocks with the task of keeping trains rolling. The Dispatcher would be at the Central Traffic Control panel, often with no view of the layout. CTC is a large expense and very complex to implement, so only large layouts featuring Class 1 operations would have one.
Other implementations include Progressive Cab Control, where power routing for a cab was done automatically, usually by a computer driving relays, and Master Zone Layout Control.
Differences in Digital Command Control
Digital Command Control implements blocks as power districts. They do not serve the same purpose as blocks would in cab control situations. Power Districts are used to isolate multiple boosters or to manage power distribution and isolate faults from the rest of the layout. In DCC, unlike cab control, multiple trains can be operating in the same power district, controlled by multiple operators.
This directly enhances operations, as the engineer no longer has to worry about trespassing in another block, and various prototypical operations can be replicated easily. No longer is a long cut of cars needed to move a few cars because the switcher can't come into your block, and can't reach the needed place without them.
According to the Flagstaff Model Railroad Club, the Dispatcher's duties include:
- Maintains final authorization over the movement of freight and passenger trains. All operators must obtain permission from the dispatcher prior to movement of railroad equipment anywhere along, or involving, the main line.
- Responsible for operating block control and mainline turnout toggles on the dispatcher's booth control board.
- Communicates with each yard master regarding train movements into and out of yard limits.