Yellow stripe restrictions under the wires

[Legend]

I’ve just been watching a DVD  Railways of Scotland ~vol 6 Glasgow . In it there is quite clearly a Duchess with the stripe restriction  but it’s under the wires at Glasgow Central. Later on there is a similar picture at Motherwell . I know initially some of the Scottish electrification was at 6.25kv , perhaps that’s the case at Central but I’d be surprised if it was 6.25kv at Motherwell . So my question is , was the stripe restriction just south of Crewe and if so why did it not apply to Glasgow /Motherwell area . I’ve watched this DVD several times and it’s never dawned on me before that these restricted locos are actually under the wires north of the border .   

[phil-b259]

7 hours ago, Legend said:

I’ve just been watching a DVD  Railways of Scotland ~vol 6 Glasgow . In it there is quite clearly a Duchess with the stripe restriction  but it’s under the wires at Glasgow Central. Later on there is a similar picture at Motherwell . I know initially some of the Scottish electrification was at 6.25kv , perhaps that’s the case at Central but I’d be surprised if it was 6.25kv at Motherwell . So my question is , was the stripe restriction just south of Crewe and if so why did it not apply to Glasgow /Motherwell area . I’ve watched this DVD several times and it’s never dawned on me before that these restricted locos are actually under the wires north of the border .   

 

The stripe was all to do with what we would term the flashover potential on a specific route  and not an absolute ban on using the locomitive under AC OLE!

 

South of Crewe there were a few specific locations where the clearances were such that a flashover from 25KV to certain locomotives types could occur and the painting of a yellow stripe on the cab was determined as the easiest way of providing a reminder to railway staff that said loco could not work south of that point.

 

Therefore the yellow stripe could be ignored because Glasgow (or Motherwell) are not south of Crewe.

 

 

Edited January 17 by phil-b259

[Right Away]

Further to this topic, does any member know if there was an actual threshold of dimensions specified by BR (LMR), above which, any locomotive would be barred from operating under the energised 25kV catenary south of Crewe? Would it have been a simple “the tallest height of any part of a locomotive from rail head must not exceed  a certain amount” or a rather more specific directive?.

 

Note: A Stanier 5MT with standard LMS chimney having a maximum height of 12’ 8” was permitted, whilst an 8F with 12’ 10” height, was barred. 

 

In addition, what directive pertained to the operation of “foreign” locomotives “under the wires” and were any such directives ever transgressed?

 

[Wickham Green too]

I think the only 8Fs barred were the final three inherited from the Military as they had non-standard top feed covers ............. in theory, at least, as 48773 had a standard top feed by that time.

[LMS2968]

I think we've been through the 8F and yellow stripe situation before, but the three ex-Middle East engines, 8773/74/75, were fitted with bigger top feeds containing shut-off valves  to deal with the atrocious water in the desert. The valves were operated by a vertical spindle, one each side, and these spindles were above the loading gauge limit; no other 8Fs were involved. When the stripe appeared, 8773 was given it; 8775 had had its spindles cut off so was exempt, while 8774 still had the spindles but didn't get the stripe. In 1966, 8773 had a Heavy Intermediate overhaul at Crewe and was given a new boiler, the opportunity was taken at the same time to fit a standard top feed so she became within the loading gauge. Despite this, the stripe was reapplied and carried until withdrawal in August 1968.

[MidlandRed]

17 hours ago, phil-b259 said:

 

The stripe was all to do with what we would term the flashover potential on a specific route  and not an absolute ban on using the locomitive under AC OLE!

 

South of Crewe there were a few specific locations where the clearances were such that a flashover from 25KV to certain locomotives types could occur and the painting of a yellow stripe on the cab was determined as the easiest way of providing a reminder to railway staff that said loco could not work south of that point.

 

Therefore the yellow stripe could be ignored because Glasgow (or Motherwell) are not south of Crewe.

 

 

Interestingly the remaining ex LNW 7Fs in the West Midlands had the stripes, but were withdrawn before electrification reached the area. Presumably they weren’t permitted on duties which took them to places like Nuneaton or Rugby? However I do wonder whether the ‘not allowed south of Crewe’ is actually correct or whether the restriction was more precise than that. I recall seeing occasional Stanier Coronation Pacific class locos on diverted passenger services via the Grand Junction route in Perry Barr at weekends whilst the Trent Valley was closed for electrification works - begs the question whether they had operated under the wires between Crewe and Stafford. The stripes appeared after electrification north of Crewe (and possibly north of Stafford). Perhaps places like Kilsby Tunnel and those further south were affected by the restriction? 

[Poor Old Bruce]

As far as I am aware, it was the OHLE south of Stafford that was put up with some reduced clearances. Locos which eventually received the yellow stripe were happily working to (through?) Stafford up to the time that the OHLE was energised south of Stafford. I assume that Crewe was chosen as the changeover point because there were better resources there to actually do it. Nearly all trains stopped at Crewe in those days whereas many didn't stop at Stafford.

[Poor Old Bruce]

6 hours ago, Right Away said:

Further to this topic, does any member know if there was an actual threshold of dimensions specified by BR (LMR), above which, any locomotive would be barred from operating under the energised 25kV catenary south of Crewe? Would it have been a simple “the tallest height of any part of a locomotive from rail head must not exceed  a certain amount” or a rather more specific directive?.

 

Note: A Stanier 5MT with standard LMS chimney having a maximum height of 12’ 8” was permitted, whilst an 8F with 12’ 10” height, was barred. 

 

In addition, what directive pertained to the operation of “foreign” locomotives “under the wires” and were any such directives ever transgressed?

 

I think the limit was 12ft 10in.

[Clive Mortimore]

In the 1960s apart form the pantograph the closest anything can be to a live 25Kv AC contact wire was 11 inches to prevent a flashover. 

 

The lowest the contact wire can be is 13ft 9 ins.

 

The tallest rolling stock that could safely travel under 25Kv AC was 12ft 10ins, as stated by Poor Old Bruce.

 

Since the 1960s the clearance has been reduced to 9inches under certain circumstances, hence many preserved steam locos that were banned can now chuff along under OLE wires.