Max speed through Swindon and an idea further west

[whole diary]

[John R]

About 6 years ago the maximum speed through Swindon was reduced from 125(?) to 85, when the up turnout at Rushey Platt was improved to enable a faster entry to Platform 3. By reducing the linespeed to 85, it removed the need to have the turnout approach controlled, as the diverging speed is only 10mph lower.

At the time it was (rightly) justified as the number of services passing through Swindon without stopping were very low (maybe just one each day). However, with IEP^▸ (Intercity Express Program / Project.) coming, draft timetables indicate that there could be at least one if not two each hour.

So, would it make sense to reinstate the higher speed, which would mean that trains travelling from the Hullavington route wouldn't have to slow to 70 for Royal WB, then accelerate back up only to slow again a couple of minutes later?

Talking of Royal WB, a slightly (ok, maybe more than slightly) off the wall thought is to grade separate the down Hullavington, running just to the south of the aggregate depot. As well as the benefit of removing the conflict with the Up route from Chippenham, it could a) increase the line speed on the South Wales route, b) enable the current up loop to be moved slightly further west and c) that would create space for a station immediately east of the junction, with fewer issues with pathing stopping trains.

Unlikely? Well, there are several similar schemes either recently completed (Hitchin, Nuneaton North), in progress (N Doncaster Chord, Ipswich curve) or well advanced in the planning process (Norton Bridge). And whilst the business cases for all these schemes are different, they demonstrate the benefit of incremental improvements in the railway infrastructure.

[4064ReadingAbbey]

Your proposal to grade separate Wootton Bassett Junction has, I would suggest, merit. As generally the number of trains per hour per line has been steadily increasing year for year over the last two or three decades the incidence of delays caused by conflicting movements has increased - and on this route especially the traffic density will increase again with the introduction of the Super Express Trains (aka IEP^▸ (Intercity Express Program / Project.)) on the Bristol route. Grade separations are especially valuable where long freights can block junctions for extended periods compared to shorter and more rapidly accelerating passenger trains.

You correctly point out that Network Rail is spending money on several grade separation schemes at the moment in various parts of the country, there are three on the Western alone - Acton Yard, additional bridges and tracks at Airport Junction and those at Reading. I would hope that these, and the others that you mention, would be the start of a rolling programme. In the first instance I would suggest that potential sites on the Western would be where the train density is highest, for example Didcot, Westerleigh Junction, Bristol Parkway to separate the Bristol and South Wales flows and Southcote Junction in Reading where the Newbury and Southampton routes part company. This later sees, roundly, a Freightliner train per hour in each direction on the Southampton route and if these could be kept separate as far as possible from the increasing number of trains on the Newbury route (possibly by a third track as far as Oxford Road Junction) then the Reading area would cease to be a major source of delays.

Grade separated junctions are seen to be expensive, but I am not sure this is necessarily the case on a whole-life basis. Once they have been built the infrastructure is practically permanent - bridges last for 100 years and more. On the plus side trackwork can be simplified and the on-going maintenance is eased as the track-to-track alignment is no longer so critical. I have read somewhere that the cost of a Signalling Equivalent Unit (a point end or a signal, etc.)  is in the region of ^300k quite apart from the Civils' costs. So taking out a couple of turnouts (sorreee!) and some of the associated signals would save something like ^1million.

I would expect such a programme to exist in its own right - but it should be that such issues are considered whenever a large civils or re-signalling scheme is being considered.

[IndustryInsider]

Agree with both posters' comments.  Wootton Bassett Junction is an ideal candidate for future grade separation with the number of trains likely to increase, and the opportunity to dramatically increase the linespeed as a result would help the business case.  I would put Didcot East Junction higher on the list of schemes that will be needed as I can see that becoming the pinch point on the GWML^▸ (Great Western Main Line) following the improvements at Reading, and Southcote Junction isn't far behind in that regard.

There will always be pinch points of course as whenever you spend money at one location which allows for more trains, the next location starts to struggle more, but those three locations would benefit now let alone in the future, and are more important, in my opinion, than further redoubling of the Cotswold Line for example.

[brompton rail]

Just as a point of interest, the Doncaster North Curve (actually at Joan Croft, some 5 miles north of Doncaster) is not a grade separated junction. The new line crosses the ECML^▸ (East Coast Main Line) by bridge, otherwise a flat junction would be required! It is a new line linking the Immingham line with the Knottingley line to allow freight direct access  towards Yorkshire Power Stations. without travelling along the 125mph East Coast main line. Direct and shorter route for freight (imported coal), reduced freight on ECML, greater reliability for ECML High a Speed services.

[John R]

Neither is the Ipswich chord even grade separated. They were examples of infrastructure improvements, though at least the Doncaster one does involve rail over rail.

[Gordon the Blue Engine]

Agree with both posters' comments.  Wootton Bassett Junction is an ideal candidate for future grade separation with the number of trains likely to increase, and the opportunity to dramatically increase the linespeed as a result would help the business case.  I would put Didcot East Junction higher on the list of schemes that will be needed as I can see that becoming the pinch point on the GWML^▸ (Great Western Main Line) following the improvements at Reading, and Southcote Junction isn't far behind in that regard.

There will always be pinch points of course as whenever you spend money at one location which allows for more trains, the next location starts to struggle more, but those three locations would benefit now let alone in the future, and are more important, in my opinion, than further redoubling of the Cotswold Line for example.

Agree strongly re Didcot East Junction. As I've said before I think all XC^▸ (Cross Country Trains (franchise))'s should run ML between Reading and Didcot and vv to maximise route capacity after trackworks west of Reading are completed.  Interesting to try drawing on paper exactly what flyover you'd put in, and where it would land at each end.

[JayMac]

Remembering also that dive-unders can be an option depending on topography.




Edited to remove grocer's apostrophe.

[John R]

Maybe there is room at Moreton Cutting?