Is it really about expresses or about freight paths?

[whole diary]

[grahame]

For the next four weeks (Monday to Friday only, and with an exception on 13th July), TransWilts daytime trains will be replaced by buses and peak trains are retimed.   This is said to be to allow paths for express trains from the West of England to be divertd away from the line from Westbury to Reading via Newbury, which is shut for electrification work.

Rather curiously, Saturday and Sunday local trains look to be scheduled to run more or less as normal for this period, and I note some 19 freight paths (mostly marked "Q") passing along the single line section on each day this week.

Questions ... I wonder if our rail experts here can help

1. Bearing in mind that Saturday and Sunday are "as normal" and yet the line through Newbury is still closed, is it really the long distance expresses that are the straw that breaks the camel's back, or is it those freight trains that might (or might not) be running?  "Other passenger trains" is after all likely to be a more acceptable reason for passengers than "we have to run stone trains"

2. Since timetables have been recently changed to meet the engineering needs, would it be reasonable to assume that the changes also cover any reduction in service due to having fewer trains and crews available that might have been anticipated some 12 months ago when the (un-engineered) timetable was drawn up, or can we expect further very late notice cancellations and diversions?

Peak commuter services are scheduled to run, as are weekend services, with rail replacement buses scheduled off peak Monday to Friday.  And it's the railway's duty to provide alternative transport in the event of further last minute cancellations which make a massive difference to your travel plans.

Passengers between Trowbridge / Westbury and Chippenham / Swindon may travel via Bath Spa with a change there, on a lower priced "via Melksham" ticket, if their normally timetabled journey isn't practical during this period.  That's things like the morning train from Brighton which normally connects (7 minutes) into the TransWilts train, but for these four weeks arrives into Trowbridge 7 minutes after the bus has left!

Off peak tickets will also be accepted on the 2nd train from Swindon in the morning, even though it's running 25 minutes earlier than normal, and before the magic 08:49 cut off.

Thanks to GWR^▸ (Great Western Railway) for implementing these two concessions / morally the "only right thing to do" in my view, as the idea of the industry charging people more for its own closures / changing of normal services is pretty hard to defend!

[stuving]

Is this relevant? Probably not, but never mind.

SNCF^▸ (Societe Nationale des Chemins de fer Francais - French National Railways) have built a "new generation mixed line", and last week announced the latest stage of its opening. That's mixed as in goods and passenger trains, and new generation in that the passenger trains are TGVs^▸ (Train a Grande Vitesse).

We are talking about the Contournement (bypass) de Nîmes et Montpellier, which opened for goods trains last December. There are two new stations on it, and the first of those - gare de Montpellier sud - opened, in that trains started using it, last Saturday. The ceremony was cancelled because the mayor of Montpellier and the president of the region are having a spat (though at least it is about trains).

It really is just on the south-eastern edge of the city, within 4 km of l'oeuf (43°35'39.45" N   3°55'20.57" E). However, it's official name is gare de Montpellier-Sud-de-France - hardly helpful, except for Bristolians - replacing the earlier suggestions of gare de Montpellier-Odysseum and gare de La Mogère, Everyone expects the obvious tram line (1) to be extended there, but there is currently no actual plan to do so, just talking and shuttle buses.

The other station is the gare de Nimes-Pont du Gard. That suggests, correctly, that it's not near Nimes; actually it's 12 km from the centre, near (not very) to  Manduel and Redessan (the station had initially been called Gare de Nîmes-Manduel-Redessan). It also suggests, incorrectly, that it's somewhere near Pont du Gard; it's 20 km away. Its opening was to be in December 2019 but has been delayed by something or other to sometime or other.

So what is the new generation way to make this traffic mix work? It's 60 km long, 50 km between the two stations, currently signalled for 220 km/hr. Their design is part of it: only Montpellier-sud is complete enough to see this on Google Earth. There is a central island platform, three tracks either side, then an outer island each side and space for a fourth track at its outer face.

That allows for one or two goods loops for regulation, and the rest must be down to timetabling and the speed of the goods trains. They say that 70% of those are already using this line, so freeing up space on the old one through Montpellier and loads of other towns. I presume enough of the goods trains are fast intermodal/container ones, many international, for a simple fixed-slot sharing (or TDMA) approach to work.

But really, the key appears to be that only 13 TGVs per day (both directions together) are planned. So there will be plenty of gaps for the goods trains. Put another way, it couldn't really be justified as a pure LGV^▸ (Large Goods Vehicle), but adding goods capacity and freeing space on the old lines bumps the BCR^▸ (Benefit Cost Ratio) over the threshold.

[grahame]

Is this relevant? Probably not, but never mind.

It's a very interesting study - though perhaps a bit distant metrics-wise from my TransWilts question.    Rather than providing data about the current limits on the single tread we have, it does provide a case study as we look towards widening from that single thread, and what can then be done.

SNCF^▸ (Societe Nationale des Chemins de fer Francais - French National Railways) have built a "new generation mixed line", and last week announced the latest stage of its opening. That's mixed as in goods and passenger trains, and new generation in that the passenger trains are TGVs^▸ (Train a Grande Vitesse).

The mixed traffic, with different performance metrics, is an interesting study.   The GWR^▸ (Great Western Railway) main line east of Reading is headed towards "peas in a pod" where the main lines (at least) will have traffic maximised by all being of a similar envelope.  To the west of Reading, though, with freight and Cross Country too, and much more interaction between the lines as far as traffic distribution is concerned, the model's a bit different.

But really, the key appears to be that only 13 TGVs per day (both directions together) are planned. So there will be plenty of gaps for the goods trains. Put another way, it couldn't really be justified as a pure LGV^▸ (Large Goods Vehicle), but adding goods capacity and freeing space on the old lines bumps the BCR^▸ (Benefit Cost Ratio) over the threshold.

And that makes sense.