Signal Passed at Danger

Flying Phil said:

Not an expert at all, but the controls on a steam locomotive are very crude devices mechanically and it is the skill of the drivers to get a smooth operation. To get the steam brake or vacuum brake to have an effect is a matter of several seconds, unless they are already being gently applied.

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Agreed, it is nothing like putting your foot on a brake pedal in a car. When the first tender wheels dropped off there will have been a "what the **** was that?" moment in the cab, and a delay while the crew realised what had happened. There will then have been a delay in them applying the brake, and a further delay in the brake becoming effective.

It is possible that as the loco was only going slowly, and if the tender wheels were well-enough sprung, they may have thought it a rough joint, and only realised what was happening when the second set of wheels went off.

ComUtoR said:

Can you explain this further please. I really don't understand your comment and neither do I believe its accurate.

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The SPAD controls in interlockings and control systems have gone through numerous iterations over the decades. At one point, it was proposed that if the interlocking detected a SPAD then it should replace all signals in that area to red. It had to be pointed out to the operators that this would mean that a signaller authorising a train to pass a signal at red would result in all signals in that area being replaced to red, as the interlocking is unable to differentiate between an authorised and an unauthorised SPAD.

The SPAD detection systems in certain modern control systems can be overridden to allow a signaller to authorise a train to pass a red signal without triggering a SPAD alarm. However, even where this feature is provided, for technical reasons until recently it was not possible to pass this through to the interlocking, which would still consider it a SPAD, and react accordingly.

In all the discussions we had with senior operators and signallers, not once did they use the term SPAR. As I recall they had a list of the different types of SPAD (driver error, last-minute reversion, signaller error, signal fault, brake fault, poor adhesion, etc.) and train authorised to pass was just another on that list.

Belperpete said:

In all the discussions we had with senior operators and signallers, not once did they use the term SPAR. As I recall they had a list of the different types of SPAD (driver error, last-minute reversion, signaller error, signal fault, brake fault, poor adhesion, etc.) and train authorised to pass was just another on that list.

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I know very little about SPAD alarms and Interlocking so I will accept that portion.

SPAR is new and has been around for a few years now. The old SPAD categories no longer exist and every time a signal is passed at Red it is considered to be an 'Operating Incident'. What then happened is that TOCs kinda revolted and the old Category A SPAD still remains. I will check, but as far as I remember the old categories never had 'Authorised' as part of their category.

When we are authorised to pass a signal at Red, there is little more than a one minute conversation between the Driver and Signaller and you go past without any problems. This is never recorded as a SPAD and is part of the every day operation of the railway. Happens all the time. SPADs are recorded and are publicly available should you wish to check which SPADs have occured. When a signal has been SPAD'ed more than once in five years, it is considered to be a 'Multi-SPAD' and is also specifically recorded and listed; also publicly available.

The Rulebook aslo makes a distinction between movements being authorised or not. The Rulebook also allows for signals to be passed on your own authority.

IF all signals that were passed at Red were considered SPADs then you would have thousands of multi-spad signals across the network.

I'm still not convinced by this SPAR business. When it was initially briefed to us (as a signalman, at the time), explained as a distinction being drawn largely for reporting purposes, we were told that (former) Cat A SPADs would continue to be referred to as SPADs, and that the others would be referred to as "operating incidents". It makes sense - passing one at danger through driver error (for example) is very different to the signal being replaced to danger (legitimately or otherwise) but the route beyond being held by the interlocking.

SPAR was never mentioned and seems to have crept in as an unofficial, albeit widely-used, term.

The definition of a multi-SPAD signal includes only (former) Cat A SPADs, not "operating incidents", and properly authorised movements past a signal at danger aren't included in the former categories or the "operating incident" definition at all.

We have had 2 official SPARs I remember reading a report somewhere that mentioned it in an official capacity. I think its a good term and easily understood. I've been through many Reds and having the distinction feels right. In old money I would of had a SPAD Cat B and a SPAD Cat C.

There is also the "thinking distance" as per your highway code, where the crew realise something is wrong and then take action to consider. Also was this ECS and the continuous brake in action or loco brakes only. (I am referring to the GCR incident)