Looe Valley Line - Signalling

Signalling

The line is supervised from the signal box at Liskeard, which also controls the entry and exit from the branch onto the main line. A complication arises because of the existence of the Coombe to Moorswater freight line, thus the entire branch line is divided into three distinct single track sections controlled by either tokens or wooden staffs.

1. The section from Liskeard to Coombe is operated under the authority of a Tyers No. 9 Electric Token System. This consists of a pair of electrically interlocked machines, one in the Liskeard signal box and the other located in a hut at the No. 1 ground frame. The pair of machines only allow one token to be removed from either machine at any one time. However, the system has been modified to allow the token to be removed from and returned to the machine at Liskeard without the co-operation of a signalman at the Coombe machine as that machine is normally unstaffed. Single track token machines normally require the co-operation of both signalmen to ensure that the train is properly offered and accepted.
2. The section from Looe to Coombe is operated under the authority of a wooden staff, which has a key attached that unlocks the No. 1 ground frame, allowing the points to be changed to give access to the Looe branch.
3. The section from Moorswater to Coombe is operated under the authority of a separate wooden staff, which also has a key attached that unlocks the No. 2 ground frame, controlling the trap points at the north end of Coombe station.

The train driver is only permitted to enter a section when in possession of the correct staff or token. There is a gap between the three sections at Coombe, but as the No. 1 ground frame (at Coombe Junction) and the station are visible from each other this section is regarded as being within the "station limits" of the ground frame (the "signalbox"). That is, all movements around the No. 1 ground frame through to Coombe station must be under the authority of the guard's hand signals (the guard acting as signalman as far as the line's operation is concerned).

The Moorswater section has a fixed "stop board" protecting the station. Similarly, the Looe section has a stop board before the points at Coombe Junction. There is no stop board on the Liskeard section because the points must be locked in position to allow access to the ground frame's station limits, otherwise the Looe branch staff cannot be removed from the ground frame. The stop boards are fixed signals and a train may not be driven past without authority from the guard operating the ground frame.

The Liskeard-Coombe Token is rarely surrendered at Liskeard until the end of the day, unless a goods train is scheduled to run through while the train is there. At Coombe Junction it used to be surrendered to the train's guard, who would place it in the token machine at the No. 1 ground frame and then use the Coombe-Looe staff to unlock the points, allowing the train to proceed back through the junction onto that section. However, in practice, the guard usually retains the token for the journey to Looe (in his capacity as signalman) as other trains rarely use the line today. The points are then returned to normal, allowing a goods train to traverse the branch if required, and the staff is given to the driver as authority to proceed to Looe and return. The token machine at Coombe is rarely used these days and indeed the hut that contains it is usually kept locked.

A goods train will similarly use a Liskeard-Coombe Token, surrendering it to the guard who, on this movement, will insert it into the Coombe token machine. The guard will then collect the Coombe-Moorswater staff, which is kept in the token machine hut, giving authority to enter the section to Moorswater. The points at the No. 1 ground frame are not changed for this movement, but a set of trap points, by the Coombe No. 2 ground frame at the north end of the station, must be opened and then closed again once the train has passed over. Since the driver of a goods train has to pull a considerable distance beyond the No. 2 ground frame he must physically touch the staff before proceeding out of Coombe station. However, the guard has to retain possession of it in order to operate the trap points again once the train has passed. Thus the Moorswater branch is actually operated by a variation of the staff and ticket system, the guard's verbal instruction to proceed taking the place of the ticket, once the driver has touched the staff. Once the trap points have been reset, the guard can give the staff to the driver.