SIGNALBOX METHODS
Signals: signal box lever colours (B.R.)
Red: Stop signals, shunting signals
Yellow: Distant signals
Black: Points
Blue: Facing point locks, clearance bars, bolt locks
Brown: Level crossing bolt lock, gate stops and wicket gates
Green: Gongs, electric ground frame release
Black/white striped: fog signals
White: spare
Signals: signal box bell code (early B.R.)
| Call attention | 1 |
| Is line clear for: | |
| Express passenger train; breakdown train proceeding to emergency; light engine going to assist disabled train | 4 |
| Ordinary or excursion passenger train; mixed traffic train; breakdown train in transit | 3 pause 1 |
| Branch passenger train (applicable only where special instructions are given) | 1 pause 3 |
| Livestock or perishable train composed of coaching stock | 5 |
| Empty coaching stock | 2 pause 2 pause 1 |
| Livestock or perishable train composed of goods stock; express goods train | 1 pause 4 |
| Through goods, mineral or ballast train | 4 pause 1 |
| Stopping goods or mineral train | 3 |
| Branch goods, mineral or ballast train (applicable only where special instructions are given) | 1 pause 2 |
| Light engine; two engines coupled; engine and not more than two brake vans | 2 pause 3 |
| Ballast or other train requiring to stop in section | 1 pause 2 pause 2 |
| Platelayers trolley requiring to pass through tunnel | 2 pause 1 pause 2 |
| *Train entering section | 2 |
| *Assistant engine at rear of train | 2 pause 2 |
| Train out of section; obstruction removed | 2 pause 1 |
| Obstruction; danger | 6 |
| Blocking back Inside home signal | 2 pause 4 |
| Outside home signal | 3 pause 3 |
| Stop and examine train | 7 |
| Cancelling signal; caution signal | 4 pause 3 |
| Train passed without tail lamp | |
| To cabin in advance | 9 |
| To cabin in rear | 4 pause 5 |
| Train divided | 5 pause 5 |
| Shunt train for following train to pass | 1 pause 5 pause 5 |
| Vehicles running away on wrong line | 2 pause 5 pause 5 |
| *Section clear but station or junction blocked | 3 pause 5 pause 5 |
| Vehicles running away on right line | 4 pause 5 pause 5 |
| Opening of signal cabin | 5 pause 5 pause 5 |
| Testing block indicators and bells | 16 |
| Closing of signal cabin | 7 pause 5 pause 5 |
| *Time signal | 8 pause 5 pause 5 |
| Lampman or fog-signalman required | 9 pause 5 pause 5 |
| Testing controlled or slotted signals | 5 pause 5 pause 5 pause 5 |
* not preceded by the 'Call attention' bell
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Subsequently some codes became redundant or were reclassified as follows:
| Express parcels or perishables running at 90mph or over | 1 pause 3 pause 1 |
| Freightliner train | 3 pause 2 pause 5 |
| Parcels train running at 75mph or over | 3 pause 1 pause 1 |
| Fully fitted block train | 5 |
| Ordinary freight train | 4 pause 1 |
| Unfitted freight train | 1 pause 4 |
| Line clear to home signal (and cancelling signal) | 4 pause 3 |
During an interim period of the early 1960s, when unfitted freight stock was being progressively phased out, various bell codes were used to indicate the proportion of fitted vehicles in a given train or its limited load. These were various permutations of five bells, although '3' and '1 pause 2' were retained as above.
