Signal box
|
The mechanical signal box controls. The cables from the levers cross the floor, leading to the signals and switches on the railway |
A
signal box or
signal cabin is a
building from which
railway signals and
points are controlled. Originally all signalling was done by mechanical means; cables or rods, connected at one end to the signals and turnouts and at the other to levers in the signal box, ran alongside the railway. This required signal towers to have complex arrangements of cabling, levers and pulleys. The guts of this system was the
lever frame, wherein one finds this complex cabling arrangement and linkage to levers and controls.
Nowadays, some old-style signal cabins can still be found. Some still control
mechanical points and signals. More often than not, the frame has now been removed or is out of use. This is due to widespread power signalling. Most modern countries have little, if any, mechanical signalling remaining in the rail system.
The modern control centre has replaced widespread signal cabins. These centres, usually located near main
railway stations, control the track network using computer systems. One such system is
CTC, Centralised Traffic Control.
In the UK typical modern signal boxes are of the
Integrated Electronic Control Centre or IECC, Entrance-Exit panel (NX) or One control switch (OCS) type. Variations of these control systems are throughout the world.
Image:Signal box and train.jpg|A traditional UK signal boxImage:Signal box inside.jpg|Inside a signal box on the Isle of Wight Steam RailwayImage:Patrickswell_signal_box.jpg|A disused signal box at Patrickswell, County Limerick, IrelandImage:Signal box Bangor.jpg|Main line UK signal box still in use at Bangor*
Interlocking tower*
Everything you need to know about mechanical signal boxes*
Over 100 photographs of traditional mechanical signal boxes on Britain's rail network*
Free simulations of several British IECC signal boxes
