Train Graphic
Great Western Passengers' Forum [home] and [about]
Current travel advice (early 2021)
Forum in and beyond Coronavirus
Travel & transport from BBC stories as at 09:35 01 Mar 2021
- Jobless rate around UK airports above average, say MPs
Read about the forum [here].
Register [here] - it's free.
What do I gain from registering? [here]
 today - End, Bath Transport consultat.
03/03/21 - South East On Track - ONLINE
08/03/21 - School (travel) returns
09/03/21 - Tuesday Club - ONLINE
Random Image
Train Running Polls Acronyms/Abbreviations Station Comparator Rail news GWR co. site Site Style 1 2 3 4
Next departures • Bristol Temple MeadsBath SpaChippenhamSwindonDidcot ParkwayReadingLondon PaddingtonMelksham
Exeter St DavidsTauntonWestburyTrowbridgeBristol ParkwayCardiff CentralOxfordCheltenham SpaBirmingham New Street
March 01, 2021, 09:40:50 am *
Welcome, Guest. Please login or register.

Login with username, password and session length
Forgotten your username or password? - get a reminder
Most liked recent subjects
[167] Regular commuters: What are your current plans and preference...
[93] Terrible day in UK rail history 28 February
[84] Bow Street Station (Aberystwyth) opens 14.2.2021
[55] A new name for the organisation that runs the railways
[46] Top ten worst places to live in England - comes to GWR land th...
[32] Friday 28th February 2020 - Greta Thunberg in Bristol.
News: A forum for passengers ... with input from rail professionals welcomed too
 
   Home   Help Search Calendar Login Register  
Pages: [1]
  Print  
Author Topic: Single line capacity - is an hourly passenger train each way possible?  (Read 235 times)
grahame
Administrator
Hero Member
*****
Posts: 32576



View Profile WWW Email
« on: February 20, 2021, 09:13:30 am »

From National Rail https://www.nationalrail.co.uk/service_disruptions/261162.aspx - as at this morning

Quote
Start date 20/02/2021  00:00
End date 21/02/2021

Route affected

Great Western Railway between London Paddington and Bristol Temple Meads / Exeter St Davids / Penzance.
 Also between Portsmouth Harbour and Cardiff Central
 South Western Railway between Salisbury and Bristol Temple Meads

Great Western Railway:

Buses will replace trains between Bath Spa and Bristol Temple Meads.

Some trains will be diverted between Swindon and Bristol Temple Meads and will not call at Chippenham or Bath Spa.
Until late evening, a hourly train shuttle service will run between Swindon and Bath Spa calling at Chippenham.

Trains between Portsmouth Harbour and Cardiff Central will run between Portsmouth Harbour and Swindon calling additionally at Melksham.

Customers should use rail connections between Swindon and Cardiff Central South Western Railway.

South Western Railway
It is not yet known how South Western Railway are affected by this engineering work.

Where it says "calling additionally at Melksham", actually only some of them are calling at Melksham - those which are closest to the normal train times.  Fair enough at the current time.   What this does do is show that the line can handle an hourly passenger train each way, though I grant you that lack of much freight and thinned out services on the double track main lines at both ends of the single line section makes it easier today than it would be on a typical full service weekday.
Logged

Coffee Shop Admin, Vice Chair of Melksham Rail User Group, and on the board of TravelWatch SouthWest.
grahame
Administrator
Hero Member
*****
Posts: 32576



View Profile WWW Email
« Reply #1 on: February 21, 2021, 08:34:02 am »

So ... how did they do?  "Pretty Well".




How it was run

Hourly train from Westbury at about xx:12 into Swindon at xx:54, and from Swindon at xx:24 arriving at Westbury at xx+1:02. Times varied by a few minutes (but only a few minutes) in any hour; 38 minute running time achieved in the example quoted includes stops at Chippenham, Melksham and Trowbridge. Without other trains getting in the way (key comment!) the service daily could be run clockface, hourly, using 2 x 90 m.p.h. Turbos, hourly, to these timings, on current infrastructure.

Time for passengers, Freight Paths, etc

4 minutes slower in my example Westbury to Swindon; 1 minute perhaps accounted for needed by slow approach to Platform 2 at Swindon. The two trains pass each other at or very close to Chippenham station, and an extra 5 minutes in the "cycle" from there to Swindon and back, and from there to Westbury and back (leaving turn arounds of 21 minutes and 5 minutes) would work. That five minutes allows for pathing, and for extended passenger operations at stations that will happen from time to time. The closeness of the two trains at Thingley - short gap as the up train comes off the single line before the down train takes it - leaves a path open for a freight or other working each hour. You can see this used at Melksham with none-passenger services passing at 12:08, 13:14, 16:00 and 16:14 (managed to get 2 in that hour!!)

Robustness

Service robustness of passenger trains generally good yesterday. The 17:28 call (at Melksham, northbound) was 13 minutes late, due to a delay (don't know why) to the train south of Salisbury, and that meant that the pass at 17:47 of the southbound train was 8 minutes late as it had to wait at Thingley. At first glance, it looked like an early running freight got in the way of the 17:28 as it swept through Melksham at that time, but in practise good signalling control took advantage of the gap and sent it through ahead of time.

Infrastucture improvement

We talk / look / see the need for the ability for trains to pass each other between Melksham and Thingley Junction and indeed for robustness in a fully running timetable this makes huge sense; for passengers trains, redistributing the short turn around at Westbury and the longer turn around at Swindon to be more even, and allowing a pair of freight services to similarly pass in the hour with a degree of robustness in there too.  In my view, the loop would need to be fast running and long ("dynamic") to avoid slowing / stopping trains in one or both directions to the substantial loss of positive effect from the loop by prolonging journey times.I also note the run (round trip time) of several minutes from Thigley Junction to Thingley East junction, where the single line traffic on "the Melksham Line" is sharing the main down London to Bristol via Bath line.  Prior to the singling of the Melksham line, a double junction at Thingley meant this pinch point did not exist; I understand that restoration of that, or a crossover at the junction, is complex/impractical/impossible due to the cant on the main line tracks to allow fast running.

Calling additional (new) stations?

Timings seen yesterday would appear to allow passenger calls in both directions at Royal Wootton Bassett. More difficult (and it's where the dynamic loop becomes needed) to call at Staverton and/or Ashton Park as in the Systra / SWLEP report of 2019 (mirror ((here))).

P.S.  and bit off the immediate topic. Passengers for South Wales yesterday from Trowbridge and south thereof were encouraged to change at Swindon.  Must have been frustrating (though not many long distance passengers in lockdown) with a 40 minute wait at Swindon towards Wales, and the trains at almost exactly the same time in the other direction - so a 0 or 60 minute wait.  I noted one or two where people probably made it, one or two where the train from Swansea was a few minutes late and the Portsmouth train left before it arrived, and one or two which might have repeated my memory of a couple of years ago of doors on the IET only opening after doors on the Westbury train had been closed!
« Last Edit: February 21, 2021, 08:43:24 am by grahame » Logged

Coffee Shop Admin, Vice Chair of Melksham Rail User Group, and on the board of TravelWatch SouthWest.
Do you have something you would like to add to this thread, or would you like to raise a new question at the Coffee Shop? Please [register] (it is free) if you have not done so before, or login (at the top of this page) if you already have an account - we would love to read what you have to say!

You can find out more about how this forum works [here] - that will link you to a copy of the forum agreement that you can read before you join, and tell you very much more about how we operate. We are an independent forum, provided and run by customers of Great Western Railway, for customers of Great Western Railway and we welcome railway professionals as members too, in either a personal or official capacity. Views expressed in posts are not necessarily the views of the operators of the forum.

As well as posting messages onto existing threads, and starting new subjects, members can communicate with each other through personal messages if they wish. And once members have made a certain number of posts, they will automatically be admitted to the "frequent posters club", where subjects not-for-public-domain are discussed; anything from the occasional rant to meetups we may be having ...

 
Pages: [1]
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.2 | SMF © 2006-2007, Simple Machines LLC Valid XHTML 1.0! Valid CSS!
This forum is provided by a customer of Great Western Railway (formerly First Great Western), and the views expressed are those of the individual posters concerned. Visit www.gwr.com for the official Great Western Railway website. Please contact the administrators of this site if you feel that the content provided by one of our posters contravenes our posting rules (email link). Forum hosted by Well House Consultants

Jump to top of pageJump to Forum Home Page