Signalling at Mallaig

[yorkie]

There is a train due into Mallaig at 1409, and the Jacobite departs at 1410 (in Summer).

The signalling is RETB, and I believe there is a time delay for the releasing of the token (does the driver do this as he starts to enter the platform? or does he stop the train first and then make the call?), and then the token is issued to the other train.

How safe is this connection?

I am pretty sure it's safe, as all the connections with passing trains on the West Highland Line are guaranteed due to the time delay. Also, the last train to arrive is usually the first to leave when trains cross, as their token is already available for them to accept.

 

[P156KWJ]

hmm, maybe the token send/recieve via RETB can be reissued straightaway

 

[Jordy]

Do you know that? Or is it just a random comment/thought?

 

[Ascot]

I'm guessing once the 156 gets into Mallaig, he sends the token back to the bobby at Banavie and then he sends the token to the Steam crew. But since he does not have to walk down the track, pick it up, put it in the box, put it out the other end, walk back down and give it to the other loco crew it doesn't take 5 mins as it would do with a physical token. I suppose once the rear of the train has passed the ground frame he could give up the token and was sure he was not going to roll back.

If you was going to do the connection i'd say you got chance to do it as he would still have to give up the token and then the other would have to collect it. Yes it is normally first in last out on a "TEP" not the case at Mallaig as it is a terminus and nothing is waiting as such.

 

[Tomnick]

It still takes two radio conversations to firstly surrender the 'token' to the signalman, and secondly release a 'token' to the other driver. The first train should (I'm sure!) come to a stand before the token is surrendered (to avoid distracting the driver, more than anything to do with being clear of pointwork - though that's of course an important check too!), so that'll be a minute or two.

What's the arrangement for getting the second train away? Does it just trail through points as per the passing loops on the line, or does a ground frame have to be operated - following release of a 'token' - to allow it out onto the single line? Sorry, all this RETB stuff's a bit foreign .

 

[yorkie]

Might be a groudframe too to waste a bit more time.

Looks do-able then! Not sure if I am doing it yet but it's a possibility anyway!

Sadly the Jacobite is rather expensive for a single journey

 

[me123]

Of course, there's likely to be some slack time up there. Due to the low frequency, I would imagine that FSR would want a lot of trains on time as even a couple of delays can moticibly damage their performance. In reality, it could be that the change has up to five minutes to take place assuming that the 156 doesn't use it's hypothetical slack time.

 

[37412]

The train maybe timed to arrive earlier than 1409 in the WTT, but that is shown as the public time so it includes recovery time for any late running. Not that I know that is the answer, just a thought.

 

[Ascot]

Regardless of what happens you will have time to run the width of the platform to the other before any form of exchange takes place since it is an Island platform so makes it easier.

 

[me123]

Regardless of what happens you will have time to run the width of the platform to the other before any form of exchange takes place since it is an Island platform so makes it easier.

It's an electric token, that is it is issued by the signal box and appears on a little box in the drivers cab that looks something like this:

I'm not entirely sure of the details as such, but when the train clears the block the signaller can give the electric token to the next train. I'm not sure if there needs to be phone calls or anything, but it can be done within the minute anyway.

No physical exchange takes place at all, such is the beauty of the system. It allows single-track operation without the problems caused by having only a single manual token (ie, if the next two trains are travelling North, the token will be at the other end of the line when the first train reaches the end of the block) and multiple tokens is complicated and a single fault can prove fatal.

BTW, the RETB things come attatched to most FSR (but not SPT) 156s and (I think) all INV based 158s. There are unattatched ones as well, which can be used on all other trains, including freights, charters and steam trains.

 

[Tomnick]

The driver of the arriving train must speak to the supervising signalman to surrender the token, and also confirm that he's clear of the single line, and then the driver of the departing train must request the token and obtain permission to proceed onto the single line. I'm not sure it's as quick as proper signalling (i.e. electric token block!), as that can be restored to the instrument and withdrawn again before the first train's at a stand, if everyone's on the ball! Hence arrivals and departures at Kingscote (Bluebell Railway) often being timed within the same minute.

Can't think of too many single lines (other than dead-end branches) that rely on a single staff - and those that do will more than likely have staff and ticket working which eases things slightly and does allow consecutive trains in the same direction. Nothing complicated about multiple tokens though - as long as you've got the right equipment, it's entirely safe .

 

[Craig]

I'm guessing once the 156 gets into Mallaig, he sends the token back to the bobby at Banavie and then he sends the token to the Steam crew. But since he does not have to walk down the track, pick it up, put it in the box, put it out the other end, walk back down and give it to the other loco crew it doesn't take 5 mins as it would do with a physical token.

I suspect it would take a bit longer than 5 minutes to walk from Mallaig to Banavie and back...

 

[me123]

Can't think of too many single lines (other than dead-end branches) that rely on a single staff...

Banavie box only has 2 staff members I would imagine, as there are only two workstations and they only handle about 6 trains a day in each direction! One person works the Upper Tyndrum-Malliag portion (N), the other works from Helensburgh Upper to Oban section (S). The sourthern panel controls the junction at Crainlarich, and Fort William station itself is controlled nby Fort William Signal Box.

There's not really much point having two people on one panel. If necessary, I would imagine that the S person can help the N person for a moment or two (let's face it, he ain't exactly busy!) but I'm not sure if this is allowed as such, because it would mean unmanning that station.

 

[Tomnick]

'Staff', in my post, referred to the object physically protecting the single line (call it a token if you will - I've just always known it as a staff in the case of OTW!), rather than the chaps working the box

That's exactly why RETB is the method of choice on these lines though - it's not necessarily quicker than ETB, and it almost certainly involves a lot more faffing than TCB would. In either case, it certainly couldn't handle as much traffic - but it's a great deal cheaper than either.

 

[me123]

Sorry, Tomnick It did sound a bit strange when I was reading it...

 

[Ascot]

It's an electric token, that is it is issued by the signal box and appears on a little box in the drivers cab that looks something like this:.

Hence it is called "Electronic". By where i said Island platform, it is meant as in it is easier to get from one train to the other for passengers making a change..

See http://www.signalbox.org/branches/aj/ it is about the Cambrian but same principles apply. If you was suggesting it was manually done then it would be a pain for Banavie to walk/drive to and from the TEPs to do the actions, that's usually the give away being one box and a few TEPs.

 

[me123]

I did mean that there was no physical hand-over, but I was unsure how the friver actually receives the token: if he requests it by some electronic means, or is just given it by the signallers. I am, of course, aware that it is entirely electronic and that no physical tokens are given out for the lines at all.

I thought you, in fact, were implying a physical hand-over with the cross-platform reference. Apologies for my misinterpretation.