Spads

[387star]

Where SPADS are not placed at signals will the train still stop if it passes a red?

Also difference between dead mans handle and aws? That the same thing?

 

[BestWestern]

Hi,

You're a tad confused I fear! A 'SPAD' is Signal Passesd At Danger, the actual act of a train passing the red light. What stops it, hopefully, is the TPWS, the Train Protection & Warning System. This works by placing a 'grid' between the rails, which essentially triggers the train brakes if passed when it shouldn't be, or when passed too quickly in some cases. This is what will actually bring the train to a stop following a SPAD, although it is often the actions of the Driver applying the brakes themselves, either on seeing the signal or having passed it and realised their mistake. Of course, an emergency brake application is often too late to actually prevent the SPAD itself.

If TPWS is not fitted, the train can continue past a red signal if no other attempt is made to stop it. There was an incident along these lines fairly recently up towards the midlands, in which the train concerned travelled a distance approaching four miles beyond a non-TPWS semaphore signal. The Driver was contacted by an emergency radio broadcast and instructed to stop.

As for AWS, it is unconnected to any form of 'dead mans' system, which is a totally different device. AWS sounds a warning horn or bell accordingly to advise the Driver of the aspect of an approaching signal. The Driver must operate a plunger on the desk to acknowledge and cancel the warning, failure to do so will result in the brakes automatically bringing the train to a stand. The modern versions of the 'dead mans handle' require the Driver to hit a pedal when an alarm sounds periodically, or to keep the pedal pressed at all times. Again, failure to do so applies the brakes. Hope this helps!

 

[driver9000]

The modern versions of the 'dead mans handle' require the Driver to hit a pedal when an alarm sounds periodically, or on some units to keep the pedal pressed at all times. Again, failure to do so applies the brakes. Hope this helps!

I'm not aware of any DSDs that only require it to be pressed when the vigilance alarm sounds. The presence of a foot on the DSD is needed to keep it pressed down at all times to prevent the brakes applying. Let go of the pedal for more than a couple of seconds then the brakes are applied. Not all trains are fitted with a vigilance alarm, some only require the DSD to be pressed.

 

[ralphchadkirk]

ATP can also stop the train theoretically within the overlap

 

[driver9000]

ATP works in a different manner to TPWS. TPWS is a passive system which is normally invisible, ATP constantly supervises and gives a bit more leeway should a train be outside the braking curve warning the driver to give them chance to alter things before ATP takes action. This film was made to train Western region drivers in the operation of ATP at the time of its introduction:

http://www.railnetchannel.tv/avc-view.aspx?videoid=164&categoryid=

 

[BestWestern]

I'm not aware of any DSDs that only require it to be pressed when the vigilance alarm sounds. The presence of a foot on the DSD is needed to keep it pressed down at all times to prevent the brakes applying. Let go of the pedal for more than a couple of seconds then the brakes are applied. Not all trains are fitted with a vigilance alarm, some only require the DSD to be pressed.

Ah, I had always understood that with Sprinters at least it wasn't necessary to keep the pedal depressed constantly, just when the DSD sounds - but if that's not the case I will happily stand corrected!

 

[350desiro]

Interesting topic this is! I agree with mostthings said, but Bestwestern mentioned AWS is not linked to the DSD but if I recall correctly the DSD works on atimer and if the driver doesn't move the controls for a set period if time then am alarm will sound which he has to cancel within 5 to 10 seconds if he doesn't respond the brakes apply, however if an AWS alarm is acknowledged then the DSD vigilance timer gets reset. Therefore the longer the period is until the next DSD alarm Hope this helps, apologies if I am wrong in any way.

 

[BestWestern]

Interesting topic this is! I agree with mostthings said, but Bestwestern mentioned AWS is not linked to the DSD but if I recall correctly the DSD works on atimer and if the driver doesn't move the controls for a set period if time then am alarm will sound which he has to cancel within 5 to 10 seconds if he doesn't respond the brakes apply, however if an AWS alarm is acknowledged then the DSD vigilance timer gets reset. Therefore the longer the period is until the next DSD alarm Hope this helps, apologies if I am wrong in any way.

That's a good point, AWS might well count as a Driver-input activity and 'reset' the vigilance. I don't drive the things, you'll find me at the other end, so it's not something I'm absolutely concrete on, but the basics are relatively simple. What is interesting about it though is that there seems to be a good deal of variation between certain different types of traction, which is perhaps unusual for an established universal safety system? I wonder what are the Group Standard requirements for DSD/Vig, are there any traction units which don't have it at all?

 

[350desiro]

That's a good point, AWS might well count as a Driver-input activity and 'reset' the vigilance. I don't drive the things, you'll find me at the other end, so it's not something I'm absolutely concrete on, but the basics are relatively simple. What is interesting about it though is that there seems to be a good deal of variation between certain different types of traction, which is perhaps unusual for an established universal safety system? I wonder what are the Group Standard requirements for DSD/Vig, are there any traction units which don't have it at all?

If I am correct then every British train certainly has a DSD however only modern locos/units are fitted with the vigilence alarm

 

[TDK]

If I am correct then every British train certainly has a DSD however only modern locos/units are fitted with the vigilence alarm

There are not many trains left now without a vgillance alarm, if I recall 455 never used to have them not did 150/0 but these may now have been fitted. Shunting locos don't have it either I dont think.

 

[driver9000]

I think we are getting confused between the different systems fitted. All driving cabs have a DSD either in the form of a foot pedal which is kept pressed at all times or in the case of some older trains it is built into the power handle and must also be kept pressed down. Let go and after a few seconds the brakes apply - I was told the delay is a foot changing grace period. The only cabs without a DSD are those of steam locomotives.

The universal standard for the DSD is a foot pedal that must be kept pressed while train is moving. This has been the case for many years, since BR times with the exception of their early MUs, which as I said had theirs in the power handle.

Some trains are fitted with a vigilance alarm tied into the DSD which requires the pedal to be released and pressed again to cancel otherwise the brakes apply. Vigilance alarms feature on some older locos and units eg HSTs, 87s, 150/2s etc. Movement of the power/brake handles or resetting the AWS will reset the timer otherwise the alarm will sound every 60-90 seconds. All modern traction has vigilance although there seems to be some variance as to how other controls reset the timer. I have found that the vigilance is independant of the other controls on more recent stock and sounds regardless of what I've done.

 

[ole man]

Go onto OPSWEB and register it shows you the most signals that have had SPADS, it also shows you vidoes and pictures.
It also gives you the reason the signals were passed at danger.

 

[driver9000]

Go onto OPSWEB and register it shows you the most signals that have had SPADS, it also shows you vidoes and pictures.
It also gives you the reason the signals were passed at danger.

You have to work in the industry to get a password though.

 

[BestWestern]

I think we are getting confused between the different systems fitted. All driving cabs have a DSD either in the form of a foot pedal which is kept pressed at all times or in the case of some older trains it is built into the power handle and must also be kept pressed down. Let go and after a few seconds the brakes apply - I was told the delay is a foot changing grace period. The only cabs without a DSD are those of steam locomotives.

The universal standard for the DSD is a foot pedal that must be kept pressed while train is moving. This has been the case for many years, since BR times with the exception of their early MUs, which as I said had theirs in the power handle.

Some trains are fitted with a vigilance alarm tied into the DSD which requires the pedal to be released and pressed again to cancel otherwise the brakes apply. Vigilance alarms feature on some older locos and units eg HSTs, 87s, 150/2s etc. Movement of the power/brake handles or resetting the AWS will reset the timer otherwise the alarm will sound every 60-90 seconds. All modern traction has vigilance although there seems to be some variance as to how other controls reset the timer. I have found that the vigilance is independant of the other controls on more recent stock and sounds regardless of what I've done.

Thank you for clearing that up!

 

[RPM]

Movement of the power/brake handles or resetting the AWS will reset the timer otherwise the alarm will sound every 60-90 seconds. All modern traction has vigilance although there seems to be some variance as to how other controls reset the timer. I have found that the vigilance is independant of the other controls on more recent stock and sounds regardless of what I've done.

For some reason the vigilance in the ex-FGW 165/0s (165001-005) is set up differently from the rest of the 165/0s and indeed the 168s. In the former, moving the power/brake controller through the brake steps does not reset the vigilance, only moving it through the power notches will reset it. In the rest of the fleet both the brake steps and power notches reset it. It means that when you are driving one of the ex-FGW units you often get the vigilance alarm going of just as you are bringing the train to a stand at a station which can be slightly disconcerting.

It does seem strange that there is no group standard way of setting up vigilance devices.

 

[driver9000]

It means that when you are driving one of the ex-FGW units you often get the vigilance alarm going of just as you are bringing the train to a stand at a station which can be slightly disconcerting.

The 175 and 180 do that too.

 

[ole man]

You have to work in the industry to get a password though.

I do work in the industry, don't you?.

 

[TDK]

I do work in the industry, don't you?.

I think you need to be in management to get the password however I don't think they vet you

 

[Skoodle]

I signed up a few months ago saying I was a driver, got a password no problem. (same applies to free Railpro magazine subscription)

 

[dk1]

There are not many trains left now without a vgillance alarm, if I recall 455 never used to have them not did 150/0 but these may now have been fitted. Shunting locos don't have it either I dont think.

For some strange reason 156s where never fitted with it.

 

[pendolino]

There are not many trains left now without a vgillance alarm, if I recall 455 never used to have them not did 150/0 but these may now have been fitted. Shunting locos don't have it either I dont think.

You're right, 455s don't have a vigilance device. I have to remind myself of this occasionally as when on 456s or 377s I tend to lift my foot off the DSD every now and then to reset the vigilance rather than waiting for it to go off. Obviously, if I did that on a 455, I would quickly come up in a heap, followed by an embarrassing call to the signaller.

 

[driver9000]

I do work in the industry, don't you?.

Yes. When I said 'you' I didn't you individually, I meant that Opsweb is designed for industry member and as such you need to be in the industry sign up. I find it quite an interesting site too look at from time to time.