Signal Box Electricity Supplies

Railway Signal Boxes were some of the first users of 'electronics' but how was the power supplied?

In Rural areas there was no mains power until after WW2 and Adrian Vaughan describes mains power being laid on to his box in the mid 1960's

So how was electricity provided, especially as more electrical/electronic systems were added and power operated signals and points, in particular Intermediate Block Sections prior to the provision of mains power

 

Thumping great big batteries! Someone I'm sure will have more detail

Sent from my Moto G (4) using Tapatalk

 

For telegraph instruments, and latterly track circuits, batteries would have been sufficient, and a robust technology even in the 19th century. Presumably there would be instructions in the rule books for either the signalman, or someone else, to do the necessary maintenance on the batteries.

Tom

 

... and very ingenuitive technique to make everything very power efficient.
As an example from the UK, even into the 70:ies semaphores on the Welsh lines had kerosene lamps with bimetal thermal switches to continuously monitor their function.
In the electrical point locks that we traditionally had in Sweden (I guess German technology, but could be similar in the UK?) the magneto coil that should allow the point to be operated were normally unpowered. When you operate the point the bar through the lock has a cam that lifts the plunger into the magneto coil and tries to energize the coil at the same time. If the point is free to be operated the coil just keeps the plunger in the lifted position until the operation is finished. If the point is locked, the plunger immediately falls down again and blocks the point from being operated. The electricity needed is only to hold the plunger for a few seconds. All designed to be power efficient.

 

Adrian Vaughan, in his books, describes hand cranking a 'hurdy gurdy' generator to power the point motors at Challow signal box.

 

Presumably then there would be regular replacement with charged batteries

 

Yes, I believe when the area around Toddington signal box was excavated they found quite a sizable collection of discarded batteries, obviously the S+T engineers couldn't he bothered to take them away with them!

 

A few years ago I peered inside a sample set of omnibus phones and worked out a circuit diagram - it was interesting to see how many different voltages they required to operate - originally by taking power from a bank of batteries of course. I vaguely recall there were separate feeds to the bell, to provide the ringing signal to other boxes and to power the voice circuit.

 

That was also the case were you had a fairly permanent TSR rather than a PSR.
The area would be littered with old battery's.
One good thing to thank Reflective speed boards for.

 

When the St Albans South box was taken over for preservation, a large cupboard was found full of large rechargeable 'Nife' cells which had supplied most of the power but kept trickle-charged from the mains. They were in such a state that the box was declared a hazardous area - fortunately for us a waste removal company took them away free of charge as a 'donation' to the restoration!
When mains power reached boxes, remote locations were sometimes fed with 100 volts ac via a pair of wires on the telegraph posts - usually mounted on an arm wider than the rest and in some areas on red-coloured insulators to distinguish them to the linesman.

The original batteries were the 'Wet' Leclanche cells of course; a reprint I have of a book on signalling maintenance from the 1920s/30s says that the dry cells - the batteries we use today - were expensive and saved for use in locations were the wet cells were unsuitable - indoors in offices, for example, or large ones designed for use with point motors. But there is no mention of the replacement frequency for batteries, only of tests to see if they needed replacement.