The following signal equipment can typically be found at turnouts and interlockings:
- Switch machines
- Impedance bonds
- Inductive loops including speed command loops
- Train stops
- Bootleg risers
- Junction boxes
- Switch controllers
- Electric locks
- Transponders
- Wire and cables
- Signal and power bonding
- Cases/signal equipment houses (“bungalows”)
- Signals
- Snow melter systems
The design of the track circuit and fouling protection used will determine the location of insulated joints in the special trackwork. Typically in transit applications, the insulated joint should be located approximately 23 to 25 feet [7 to 7.6 meters] ahead of the switch points to allow for the use of plug rails for bonded insulated joints. The size of the turnouts and crossovers determines the speed at which the train can operate. This speed should be one of the available cab speeds.
The insulated joint for the turnout fouling must be located with a minimum of clearance, taking into account the longest overhang from the front of the train to the first axle of any equipment that may operate on the track. Location of insulated joints at turnouts and interlockings needs to consider the distance from the signal or point of switch to ensure switch detector locking. This distance can vary from 25 feet to 50 feet.
