Track Circuits and Mansell Wheels

[bassmike]

The centre on the axle was metal. Teak wood was used, presumably because this was a hardwood and more resistant to rot.

What about woodworm? What an advert for Rentokil

 

[edwin_m]

As an aside, were the early track circuits short in length compared to todays'? I ask because, certainly in the 1970s, TCs were prone to failure when it rained, because water provided a lower resistance circuit between the rails, nearer to that of a train. This was, I think intuitively, more likely if the T/C was long but I'm not sure of that...

There's certainly a limit on track circuit length - about 500 metres with modern types. I have no knowledge of whether the historic limit was shorter, but I suspect it would have been as the rails didn't sit on insulated pads and the track itself was probably more mucky especially where trains frequently stopped. So the general level of resistance between the rails would have been less, which would probably also have made the variation between wet and dry conditions less significant.

 

[John Webb]

.....As an aside, were the early track circuits short in length compared to todays'? I ask because, certainly in the 1970s, TCs were prone to failure when it rained, because water provided a lower resistance circuit between the rails, nearer to that of a train. This was, I think intuitively, more likely if the T/C was long but I'm not sure of that...

I am informed that even modern track circuits may be divided into 'sub-circuits' although to the signaller they may be presented as just one track circuit. Again, referring to St Albans South, the two down lines each had a 'single' track circuit for some IBS (Intermediate Block Signals - colour light type) that was some 4000 yards long but made up of some 5 sub-circuits, I recall being told.

 

[DerekC]

Thank you to all who provided details of electricity supplies in response to my original query.

On the subject of the adoption of track circuits; may I suggest that the philosophy at the time was perhaps different. Reading through early accident reports on Railways Archive (to which, incidentally, thanks must be due to Rupert Dyer) the Inspecting Officers' criticisms of railway companies' failures were directed at, for instance inadequate and non-automatic brakes, but this failure I might describe as 'primary', i.e. it was a fault in itself, not one that was the result of a failure by staff to adhere to Rules and Regulations.
There never seems to be criticism of the lack of track circuiting (or, at least, some form of detection) and possibly this was because it might be thought of as 'secondary' - or of the lack of secondary safety features generally. I am using 'secondary' because it's the second line of defence against 'forgetting' a train/loco's presence; the first is the signalman not doing so, and the fireman carrying out Rule 55, i.e., adhering faultlessly to Rules & Regs..
I would suggest that the railway companies' view (and, probably, the Railway Inspectorate's) was accidents such as Hawes Junction were caused simply by failures of staff to adhere to rules and to be proficient in their duties. Blame always seems to be attributed to staff who do not perform faultlessly, rather than to railway companies for not providing back-up systems for when this happens.
It's perhaps a mistake to think that present-day opinions (for instance, that human beings inevitably make human errors) apply to the situation more than 100 years ago. I'm not trying to defend the old companies, just saying that they might have seen things from a different perspective. After all, staff were called Railway Servants and could be dismissed instantly if they weren't 'perfect' with no difficulty in finding a replacement.

As an aside, were the early track circuits short in length compared to todays'? I ask because, certainly in the 1970s, TCs were prone to failure when it rained, because water provided a lower resistance circuit between the rails, nearer to that of a train. This was, I think intuitively, more likely if the T/C was long but I'm not sure of that...

I think there is no doubt that attitudes have changed. It's also true that it has become accepted that companies have to provide defences to prevent or trap human error, but this started in the early days of railways with the introduction of interlocking, a defence against another kind of signaller error. It surprised me as well, that inspectors didn't make more recommendations to install track circuits. A very surprising thing at Hawes Junction is that the levers weren't fitted with collars - apparently not Midland policy at the time. Now that really wouldn't have cost much!