Great Western Coffee Shop

Train control question - under what conditions does a freight train get priority over a passenger train?

Yesterday evening's 17:08 from Appleford to Whatley Quarry left Appleford 2 minutes early.  It was due to stop in the loop at Swindon, but didn't - carried on 60 minutes early and came to a halt at Thingley East junction where it had to wait 10 minutes for the single line to Bradford Junction.

Directly behind from Swindon was 2O00 - Cheltenham Spa to Southampton.   That was on time at Chippenham, but had to  wait  8 minutes in the platform and a further 8 minutes at Thingley East ... shows as being 17 minutes late into Trowbridge and indeed it remained late for the rest of its run. (extra delay of 2 minutes at Melksham - 35 passenger and single door operation!)

Why wasn't the very early running freight held back, but allowed to proceed? In the process, delaying two passenger trains behind it (the following Bristol Express also got held up for about 10 minutes as the Southampton train was in the way!

Not unusual in the Didcot area.  A couple of weeks ago I was waiting at Pangbourne for a stopper to Reading.  It arrived 7 minutes late (not unusual on this operationally laid back stretch of the old GWR).  Looking at RTT a southbound freight left Oxford on time but got to Didcot North 2 minutes early, and was allowed to precede the stopper.  When we got to Reading it was sitting on Reading West curve, so it didn't gain anything.  Last week the stopper was again late leaving Pangbourne, this time for a freight running 55 or so minutes late.

As I've said before, the idea that a tight timetable with 3 minute headways can be run on this stretch of line seems a million miles from what happens to-day (as does passenger trains having priority over freights).

No logic to it, especially as this will require network rail to make delay payments to GWR.  ARS at it again or just a signaller not thinking things through?

I don't know if it is still the case but there was a problem with the points on one of the loops at Swindon earlier in the week which prevented freights being regulated there.

Its because Network Rail are in charge rather than GWR. If GWR was running the railway properly, it would have prioritised passenger services, as the freight train is not only slower but also has very little places to get out of the way. People may disagree with me, but this is why I'm in favour of bringing back the big four companies, under a fully privatised network where its not about keeping MP's, stakeholders happy or just paying a money to keep a TOC happy.
My idea is a governing board, made up of the railway management, customers, and local people who decide what's best for the railway, how to improve it and where money needs to be spent. But that's my idea!

Simplistic, but this is how it feels that the pecking order is:
1. Express Passenger
2. Engineering trains
3. Paths for engineeering trains that only run occasionally
4. Regional Passenger
5. Empties on way to run scheduled passenger train
6. Freight
7. Paths for freight trains that only run occasionally
8. Local Passenger
9. Empties on way to depot

And my (biased) view as a passenger is that this might be more appropriate:
1. Express Passenger
2. Regional Passenger
3. Empties on way to run scheduled passenger train
4. Local Passenger
5. Engineering trains
6. Freight
7. Paths for engineeering trains that only run occasionally
8. Empties on way to depot
9. Paths for freight trains that only run occasionally

In both cases, with considerable woollyness and compromise to ensure best connections, effcient use of resources (to fit everything in). And pragmatic exceptions such as engineer's trains or light locos headed out to sort a blockage or heavy lift where life and limb are involved to be absolute tops

I think your biased view as a passenger is pretty much what every passenger would say is correct.  A few freight operators might disagree though...

I am wondering, with the network so busy and scarce few free paths available, whether the industry should develop a new system for deciding on train regulation based on the likely impact of delaying a given train on other services later on.

For example, your list has express passenger trains getting priority over regional passenger trains and certainly most of the time that is probably the way it should be.  However, should that always be the case?  What if (and this sort of thing does happen) a stopper to Oxford is waiting departure from Didcot just as an express to Oxford is approaching the east avoider.  In this imaginary scenario, one is running 10 minutes late and the other 15 minutes late.  The express is formed by a Class 180 which on arrival at Oxford shunts to the down sidings and sits there for 45 minutes with the same driver on board before returning to the station.  The stopper however has a unit which shunts to the sidings and returns less than 10 minutes later.  The driver is relieved at Oxford before having their statutory break and then working a key Cotswold Line peak service to Worcester.  So, if you delay the express all you do is impact on that train, but if you delay the stopper you will be directly impacting on two other services.

Another example is regarding freight which most passengers regard as unimportant.  If a late running liner train is held at Southcote Junction for ten minutes (with nothing behind it) to allow an on time Newbury to Reading Turbo to come through then that might be considered the sensible thing to do.  If that freight is then booked to sit on Reading West Curve for 40 minutes then it probably is the sensible thing to do.  However, if that freight is then booked to run ahead of a stopper through to Didcot and then has no layover time until it arrives at Landor Street with Cross Country's and Chiltern trains bearing down on it if it runs late, then again you are going to impact on far more than just that one Newbury to Reading Turbo.  Think of our old friend 4M99 and how critical that is when it runs late, even if only 7 minutes like today.

Perhaps the industry should sit down together and work out a grading system for all trains, say from 1-10?  With a grade one being a train that if it doesn't run on time will definitely impact on several other services, through to a grade ten where it could be delayed by several minutes and would only likely affect that one train.  If two trains are vying for the next path, the train with the lowest number grade gets priority.  Naturally the longer distance trains will usually have a higher grade, but that won't always be the case and it would allow the trains that might be regarded as unimportant, but actually are important (as in the example above), to reduce reactionary delay minutes.  Similarly trains might change grade at various points in their journey when they have long dwell times at stations and sidings.

Too often I see decisions that on the face of it seem sensible cause huge impact minutes, due to situations like the one above.  Just a thought...

I looked to quote bits of that back and comment - but you're so spot on all the way though I have quoted the whole thing.  Actually, you're very much filling in on some of the stuff I hinted at "with considerable woollyness and compromise to ensure best connections, effcient use of resources (to fit everything in). And pragmatic exceptions"

I started the thread ... with a 53 minute early freight delaying a passenger train with around 40 on board by 17 minutes and another passenger train that probably had over 200 on board by 10 minutes - total passenger delay 44 hours and 40 minutes before you start counting those who joined later on their journey, and in one case a probably knock on short delay of an admittedly-quiet return train.    I'm guessing the total passenger delay added up to very roughly 55 hours, and I may be unaware of some onward missed connection or other in coming to that conclusion.

So many other examples too ... a 60 second hold on 1C89 to allow a late running 2M60 to connect would have saved 8 passenger a two hour delay in another thread - all the more galling as 1C89 started moving just as 2M60 came in alongside (6 minutes late - official connection) on the other side of the island, and the sat for 4 minutes at the next station along where it was waiting for what appeared to have been another class 2 connection.

There are, I'm sure, difference in algorithm for scheduling ahead of time and for up-to-the-minute regulation. The examples I'm quoting here are immediate regulation ones; we see the automated train departure boards making suggestions which we can laugh at - "that's not possible" and the human controller can still do very much better than those systems - but still, decisions made in a few seconds can be sub-optimal and these days we can pick back over then and criticise at our leisure, which is pretty tough on the controllers.    Occasionally we praise, but a job well done is often a job overlooked because it goes so smoothly.

For scheduling ahead of time, the biggest frustration for me as a slightly knowledgable passenger (or wannabe passenger) is the reservation of paths for trains that run less than 10 times a year, but block a useful passenger train for 250 days.  There are two such TransWilts paths which have been preventing a decent commuter service into Trowbridge, and a late afternoon train (between the 15:12 and 17:36) off Swindon.  I have noted that some late evening train times in the South West timetable via Salisbury are marked "may be varied due to engineering works" or words to that effect, and wonder how acceptable to passengers a train in the day to day timetable marked "may not run on some Thursdays due to engineering checks on the line", with the train shown a not running online from several weeks in advance, would be?

It strikes me that with a significant re-cast of express services from January 2019, everything else is thrown up in the air too and we have a real opportunity to sort out some of these quirks and ancient priorities ... and to take advantage of the electronic systems which these days provide data to people so they know of changes in a  much more intensely used system, even if the systems aren't (yet?) brilliant at actually doing the predictions.

I think they key to this is the proposed Traffic Management Systems, that are key to the future 'Digital railway' that could assist the signallers in selecting priorities for individual trains. Such systems can assess the impact of the lateness or earliness of a train further down the route. 

I agree that freight paths are important but some freight is more time-sensitive than others. Graham's point about little used freight paths is well made though.  While I would not want to block them, a little used path should probably have less priority over its timing at planning stage that an intensively used path. 

Could two little used paths be planned to be mutually exclusive - so that if the customer only wants a path a few times a year they might have to move it by a day if another such customer has their blocking path in use that day. 

In a cold unregulated railway the decision would be simply on which train would earn the most money!  There would also be a payment for having the path - whether it is used or not!

All good points.  All I would add is the need for a bit of risk management in timetable development, in the sense that delaying events such as unavoidable station overtimes, TSR’s, underpowered trains, reactionary delays earlier in the journey etc are quantified in terms of probability and consequence and allowed for.  Slightly slower timings and extra looping for freights may be the outcome, but that may be the price for a more reliable railway and thus less need for real time regulation.  In the ideal, properly timetabled railway there wouldn’t be a need for regulation.

One of the reasons that busy lines on the Swiss Railways (eg Zurich – Chur) run so well is that trains are fairly easily timed and there is thus more capacity to get back to the timetable in the event of untimetabled events.

Why not just limit freight movements to off peak hours/overnight?

Quite a lot of it is.  Given that many freight services are long distance though, it's simply not practical to park them all up in sidings for 8 hours a day.  Firstly, there's not enough room, secondly it would mean freight would lose its advantage of speed and customers would go elsewhere, and thirdly it would be very inefficient.

Running too much overnight also causes problems as some lines aren't open all night, or partially closed for engineering work.  If you look at Didcot to Reading as an example, when there's a two track railway overnight, as there often is, there's very little room for anything else to run on top of what already does, especially until around 1am when passenger services are still running.

Simply increase the delay fines on freight that break down....would encourage proper maintenance that sometimes seems as though it isn't done on a timely basis, i at all.

I’m not sure that is the answer, as freight is such a marginal business anyway and we shouldn’t be making it harder to keep freight on the rails.  Just like the old locomotive hauled passenger trains of which few remain, one engine failure and it’s game over.  In fact it can be worse than before as rescue engines are harder to find.

I general, I think that is the crux of the issue.  I remember back in the late 70's being on a class 50 (?) hauled rake of a cross-country service being stopped between Coventry and Birmingham International by a failed local EMU ahead of us.  After about a 30 minute delay we simply drew up to the rear of the failed unit under caution, and then slowly propelled it into BHI.  Caused less than an hour's delay. All the buffers and couplings matched in those days.

I think that was a well-rehearsed move back then as I had an identical experience between Smethwick and Wolverhampton.  One of the down-sides of the breakup of the national system into self-interested companies is that as well as the technical difficulties of getting different types of stock to engage with each other (I use that term as computer systems are involved as well as physical couplings) there are more complex communication systems between the various companies to agree such a move even it was possible.

Back in the day when I was working for NR and Chiltern Railways on Evergreen 2, we were slewing track at Beaconsfield to lift the 40PSR upto 70 on the up. A rather tired 07 tamper was toiling away at the London end around 02.30 on the Monday morning. Now tampers can make a fair bit of noise and all was going well. I am up at the road bridge end making sure all our gear was clear as we had to hand back at 05.30ish. Suddenly all goes quiet. Ah, get down to the other end and the tamper has sat down and blown a main gasket depositing hot but environmentally friendly hydraulic oil all over. Machine is immobile with no self  drive. Fitter called for. In the meantime, how do we move this dilapidated piece of....... No rescue locos anywhere on the patch but the only vehicle with a screw coupling to match the tamper's  is Chiltern's Bubble Car at Aylesbury.
A series of phone calls (avoiding any NR on call persons because they may not have known what I was on about) and Chiltern control agree to man up the Bubble car and bring it upto the protection near High Wycombe. Marylebone SCS fully aware of move. In the meantime fitter arrives and literally fabricates an ad hoc gasket to insert into guts of machine. It holds sufficiently to get drive and control back to tamper and limp it back to engineers siding at H Wycombe. Bubble car not needed but it could have been used. Up side -  Monday morning service ran as timetabled. Downside - speed not raised for another week and ESR imposed but no more onerous than when we started on the Friday night.
A case of who you know perhaps rather than what you know. Happy days.

A lot of likes - but where are our manners?  "Welcome to the forum, Interceptor".  I suspect that you first post was of such high quality that no-one noticed it was your first  ;D