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Hi,

My experience from last night getting home to Reading (and then missing my connecting bus) has led me to once again post a question concerning the ordering of trains leaving from Paddington or more relevantly when to put fast turbo trains on the relief line instead.

I certainly don't want to make this a moan - I'm much more genuinely interested to know more about the decision making process that occurs when several fast trains leave Paddington within a few minutes and how signallers decide the optimal order of those trains.

So what happened last night?

Because of delays to the incoming services (due to trespassers on the line) the 19.45 (to Plymouth) and the 19.48 (to Cheltenham Spa) HST services were delayed by a few minutes leaving.  However the 19.50 fast service to Oxford left on time.  A couple of minutes before the 19.50 left the screens popped up with platforms for both the 19.45 & 19.48 so I had to decide which train would get to Reading first out of those 3 choices.

I checked from the bridge which out of the 19.45 and 19.48 was dispatched first and so ended up taking the 19.48 service hoping that it would not be held up behind the slower 19.50 service.  Unfortunately, that is what happened - the train order was the slower Turbo 19.50 which stopped at Slough followed by the 19.48 and then the 19.45.

So the 19.48 travelled at reduced speed slowing before Slough and I got to Reading at 20.30 after a few minutes wait outside Reading as well.

My question is this:

Is it worth delaying 2 trains more so just to keep 1 on time?  I would have thought that the 19.48 would have got to Reading almost on time if ordered first (it left a minute or 2 late from what I recall).  The 19.45 could then also have followed at a higher speed and possibly made up time further along it's journey form any slack available.

As I say I'm just pretty interested to know how the order is decided - and whether there is scope for signallers to put the 19.50 on the relief line at the start to let HSTs overtake?

Plus I would have though FGW would rather 1 of their trains was officially late rather than having 2 that were.

Any feedback over how such decisions are made would be much appreciated!

Thanks,

Boppy.

I would imagine that the signallers were not sure when the 1945 and 1948 service were to depart, as TRTS hadn't been called.

That's probably about right. TRTS being 'Train Ready To Start' which is a button or plunger that despatch staff press when the train is all set to go (i.e. there's a driver and guard, the train is prepared, and the last of the passengers is boarding).

The signallers at Slough will (in conjunction with the Automatic Route Setting system) decide which gets preference based mainly on that, and once committed it can take a few minutes for a set route to 'die out' and another to be set, so it's more trouble than it's worth. There is also a good chance that the Slough signallers would not have the time to check that it's a Turbo and make a decision based on that - though if stopping at Slough it only adds a couple of minutes to the through timings anyway.

Though sometimes I've witnessed some decidedly sloppy signalling, so it's possible that was the case for the trains your describe too.

If Paddington is controlled by ARS, then it is possible that ARS set the route, and the signallers were not happy filling out many hundreds of forms upon cancelling a route. (120seconds before the signal is useable again) plus the miffed driver who would be on the phone to the bobby etc.

Hi,

Cheers for your replies which have answered some of the things I was wondering about.  It sounds pretty automated then!

Thanks again,

Boppy.

It main weakness of the signalling system is that the Automatic Route setting circuits are very slow and take a minute or so to set, cancel or change a route.  This means that Signallers are often loathed to change things once they are set

There is also the problem that the despatch stafff at Padd are FGW whilst the signalmen at Slough are Networkrail. Therefore all communication has to go via Swindon. Although FGW/Networkrail have a joint control it still takes time.

That's why you need a fat controller and all staff working for the same company (BR?). In BR days the duty manager at Padd would have  decided what order to let the trains out and TELL OOC box that's what was going to happen.

Throw in the delays ARS imposes changing order then it's more than likely the wrong decision about order of despatch will be made.

It's also worth bearing in mind that an Oxford Turbo is working pretty hard to keep to time and has precious little recovery time in hand, whereas the other two trains were going a lot further and have recovery allowances built in down the line. Not great if you're only going to Reading, I will concede, but the odds are other trains were right time at the end of their journeys.

Does anyone know whether the transfer from Slough to the new signal centre at Didcot at the end of next year will have any implications for the operation of the route-setting equipment? Presumably this is dependent on the kit in the signal centre.

A very interesting question. I think it comes under the Chinese curse of "May you live in interesting times". Current "new" siganalling schemes, Portsmaouth, Manchester South etc. have not gone very well, so the omens are not good for a smooth change over.

I'm not sure how much physical equipment is to be replaced in the Slough area but basically Didcot will be the new signalbox for Slough and will operate with VDUs,  ARS and SSSI interlocking, whereas Slough is currently relay locking and NX push buttons (strictly turn and push).

I could have sworn Slough was an IECC?

My memory may be failing me but I'm pretty sure Slough has (or at the very least had) both a panel box and an IECC seperately, controlling different areas.

My understanding is that Slough is a panel, and Slough New (covering Paddington-Hayes/Heathrow area) is an IECC. Similar to Swindon having two boxes, with Swindon B being the IECC covering Didcot.

But in both cases you cite, the suppliers of the kit were new to the UK network - Siemens at Portsmouth and Ansaldo at Manchester - a result of the unlamented Railtrack trying to put pressure on their existing suppliers, I think. Didcot will be a Westinghouse installation and they know what they're doing in UK conditions and are locally based, Chippenham to be precise.

Correct  :)

You all make some interesting points:

• willc - The Oxford Turbo having less slack over it's entire route is something I hadn't considered.  You're right that I'm obviously aggrieved that my train gets to Reading late but I agree that the HSTs may well have caught up their 15mins delay by the end of their journeys.  For statistics at what part of a train's journey is recording it's time done - is it just the end stop?  Does a train get recorded as late if it arrives at Reading 15mins late but arrives at Plymouth on time?
  
• Everybody's points about the various signalling panels and the modernisation of things moving from Slough to Didcot have shown me just how complicated the setup is.  Are these new signalling schemes designed to control larger areas from one location and if so will this improve things signalling wise in people's opinions?
  
• eightf48544 - Your point about having just one person in control of dispatch (like back in the BR days) is interesting as it seems to me there is an issue here.  The current joint control for dispatch sounds very bad for FGW to me as whilst they have an incentive to dispatch the trains as optimally as possible I just don't see how or why this would also be the case for Network Rail - is there some benefit they gain by re-ordering the trains that get delayed?  From the sounds of it the effort needed to sign off changing routes actually makes it a disincentive!
  

Cheers,

Boppy.

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As I understand it a long distance train is only late if it is more than 10 minutes late at its final destination.   [/list]

Correct Tim, however, should the service then effect another service (in this instance at Reading) which arrives late, then the delay minutes can be charged back to the original late running service, regardless of whether it gets to it's final destination on-time later-on.

Also, the turbo service probably has a on-time/late threshold of 5 minutes compared to the HST of 10 minutes.

Two observations I would make are:

• NR do the signallig and FGW does the dispatch - that I understand.  But why does communication between them need to go via Swindon?  Just because the people involved are working for different employers why can't they directly talk to each other (ie FGW people at Paddington directly call NR signallers in Slough.  It doesn't seem to be so much the fragmentation of the industry that is the problem here, just poor channels for communication.  If there is a good reason to stop FGW dispatch staff from calling teh 'box - prehaps because they will be a distraction? then that reason would apply under BR as well surely? 
• The point about Signallers delaying trains they know have slack illustrates the problem with putting slack in the timetable.  As soon as it is there staff (drivers, dispatch people, signallers) will be tempted to use it and less motivated to run a tight ship and minimise causes of delay.  Surely this is only human nature.  If a guard at Bath knows that his train can get to Bristol in 10 minutes but is timetables to do it in 15 he will be less worried about an ontime departure, more likely to hold the train 30 seconds for a late passenger etc in less of a rush to shut manual doors left open.

The despatch staff will directly liaise with the Signallers by using the TRTS (Train Ready To Start), as well as radio and telephone conversations. The staff at Paddington won't request the order that trains get despatched though, just advice on the status of them should there be a delay.

There is (rightly) a limit to what the local staff are authorised to do. For example, Swindon would usually get involved should a situation escalate and then FGW might suggest/request to NR that certain trains get priority, or you might get NR suggesting/demanding that FGW cancel the xx:45's to Greenford to ease congestion and so on.

The usual problems always apply though - as soon as there is a problem affecting a number of trains, both NR and FGW controllers and staff soon get swamped, and the optimal decisions are not always made. Equally a decision that might have seemed right at the time might turn out to be a mistake.

Very true, railways work in real time and that runs out very quickly. Trains leave Padd at 3 minute intervals, anything happens to delay one train unless it can be fixed in three minutes or the decision made that it can't be fixed in 3 minutes is made almost instantly the next  train will be delayed leaving.

Of course at the instance when time is running away with you Murphy's Law comes into operation which says that if you let the Turbo out in front of the HST that can't be fixed in 3 minutes the HST will be fixed in 4 minutes and follow the Turbo to Reading.

No, AFAIK if it's less than 10 minutes late at its final destination, it counts as on time. This is one of my bugbears, I reckon an XC train has around 45 minutes slack between Birmingham and Penzance, so it could be nearly an hour late at Birmingham and still end up counting as on time for statistical purposes, even though the majority of its passengers will be severely delayed.

I agree with Bemmy: in my experience, the rather generous 'timetabling', particularly for XC, does mean that a train from Manchester Pic to Bristol TM can be 'late' for most of its journey - but it then makes up most of the time and finally appears 'on time' by giving it a bit of welly beyond Cheltenham, for example!  ::)