If the South Harrow line is particularly prone to leaf-fall, and the S stock can handle the problem better than the 1973 stock, would it be possible for a couple of S stock (which already operates at both ends of the route) to be borrowed for the duration? How much modification would be needed to the line to make it usable by surface stock again?
norbitonflyer , There are a few bridges that would need to have their clearances altered, currently there are a smattering of 15mph speed restrictions around Sudbury Hill and North Ealing associated with this.
Secondly the West end of the District has a sparse enough service as it is let alone with a stretch up to Rayners Ln.
Child of Middlesex, student of the City, resident of the Metropolitan
"If the South Harrow line is particularly prone to leaf-fall, and the S stock can handle the problem better than the 1973 stock, would it be possible for a couple of S stock (which already operates at both ends of the route) to be borrowed for the duration? How much modification would be needed to the line to make it usable by surface stock again"
Good in theory, but as a temporary measure during leaf fall season it would probably be ruled out on cost grounds.
The S stock are a fair bit taller above rail height than even the D Stock which IIRC would only just fit under some bridges on the route - at very slow pace - as they were concerns the packing of the Permanent Way had raised the ballast and rail height in places since the route was last cleared for routine operation by sub surface stock.
A bit of internet digging (so not official numbers) indicates the following height to crown of roof above rail level for an empty unit (which is presumably as high as they are stationary - but as we all know trains in motion do bounce around sometimes so you would need a fair bit extra clearance?) - D stock 3620 mm - A stock - 3695 and S Stock 3686. If nothing else I suspect the whole route would need comprehensive checking (not cheap) and if that reveals the need for any substantive track lowering I doubt the cost would make sense if done simply to allow S7 stock to operate the route at normal line speeds during the limited leaf fall season. OK the cost might be justifiable if it became a permanent transfer of the branch to the District but given severe pressure on the TFL budget it seems highly unlikely.
I assume it would have to be S7s from the District to ensure they fit into the turn back siding at Rayners lane. Bye the bye there is of course one surplus S7 somewhere (the post Croxley orphan) so it might be possible to find stock.
However all that is without considering how they would work in terms of platform height and accessibility considerations, let alone things like in car route diagrams and indeed the tube map proper - as presumably this would be appear as a return of District services to Rayners or indeed Uxbridge and cessation of Piccadilly services.
Post by norbitonflyer on Jan 10, 2019 12:38:20 GMT
It was indeed the Croxley orphan which made me think there might be an odd S stock to spare.
There is of course no reason why an open air section of a "Deep Tube" line couldn't be operated by surface stock should the need arise, provided (as is apparently no longer the case on the South Harrow line) they are not out of gauge. The converse has been rather more common - 1938 stock ran briefly on the Stanmore branch when it was still part of the Metropolitan Line, as well as on the East London Line and the Northern City, whilst 1973 stock has worked to Ealing Broadway on occasion - but surface stock can run, I believe, on the Picadilly between Hammersmith and Acton Town, and the Bakerloo/Jubilee between Finchley Road and Wembley Park. And of course British Railways diesels used to run on parts of the Central and Northern Lines until the 1960s
I am fairly sure the new trains will come with some sort of wheel slip protection which should significantly reduce or largely eliminate the leaf fall issue?
However even if the new trains are perfect from day one (which remains to be seen) that improvement in performance on the Piccadilly is still a few years ahead. So it is not unreasonable to think is there anything else which TFL could be doing to mitigate the problem until then.
Earlier in this thread the idea of turning most services at Rayners Lane during leaf fall season was aired and appears to offer fairly immediate advantages of reducing Piccadilly track mileage at a time when serviceable vehicles are likely to be in short supply, with the side benefit of allowing the S8 services, which apparently are better equipped for poor rail conditions to make better progress. The idea that someone at TFL towers might be charged with devising a special leaf fall season timetable, like they do for the Met, does not seem entirely unreasonable. Whether or not that leaf fall timetable might be best achieved by using a small fleet to shuttle between Rayners Lane and Acton Town is presumably something the planners can weigh up at the same time. What people want is trains and reliable frequency.
However perhaps the most worrying announcement made by TFL recently was the decision to shelve plans to replace the Piccadilly signalling system - which already seems to be responsible for an awful lot of service issues - indeed far more than due to defective trains due to wheel flats. Personally I would prefer to be on board an old train making good progress than a fancy new one which has ground to a halt thanks to faulty signalling.
They do have a special leaf fall season timetable for the last 2 years and apparently this years was a joke trains were running late every day as soon as normal timetable came back in hardly any more late running so definitely needs to be looked at better for next year .
Problem with acton town shuttle is the reversing at acton causes even more delays to the rest of the line as takes a while to detrain. and when go into the sidings slowly no trains can go eastbound till there fully berthed on the pic line
S stocks can not run along the branch as the signalling runs at 33 1/3 Hz and might interfere between the signalling and the train.
When the moved the 92 stock between Ruislip Depot and Ealing Common Depot via Rayners Lane the train had to be isolated for similar reasons plus no tripcock installed
if thats the case how come pic shares the track with s stock at ealing acton and on the uxbridge branch ?
The signalling is fed 125hz. Ealing Broadway and Hanger Lane Junction had the track circuits changed to 125hz and the delta track circuits changed to position detectors. Uxbridge branch the vast majority of the track circuits are jointless aka JTC of the FS2500 type the others again would of had the frequency changed to 125hz
It strikes me the other reason why not, is that Pic' train operators don't sign the S Stock and District train operators don't sign the route. One group would need training, which takes them off normal duties.