The Tunnel East interlocking was the last interlocking designed, originally using 'Key Switch' relays but converted to the now standard 'Relpol' 4 pole change over relays.

The interlocking has space for 108 relays, of which 104 are in use and is the smallest of the 3.

The area of control is East of the Tunnel, hence the name, and consists of the following lineside equipment:

 7 colour light running signals

 1 two headed colour light running signal

 1 colour light shunt signal that is normally 'dark'

 1 colour light running signal with shunt signal

 1 power operated point ends with normal and reverse detection and with manual control override switches

 4 spring point end with normal detection

 2 plungers for alternate routing

 1 siding departure panel

 1 branch staff

 2 Level Crossing protection switches

 1 Treadle for SPAD

Normal movements around Tunnel East are fully automated being signalled around the circuit back to Little Moore

A plunger is provided on TE2 signal which gives the option to go towards the Branch.

A plunger is provided on TE3/4 signal which gives the option to go to the sidings.

Movements to branch require the driver to 'take' the staff to prevent another train being signalled to the branch, the driver replaces the staff when ready to rejoin the main line, which initiates the calling of the route if free, overwise waits fo it to be free.

To depart the siding the driver presses the depart button, and the signal is illuminated and the route is set

The Tunnel protection signal has a treadle which initiates the Signal Passed at Danger alarm should a train pass it when red.