Cross Arm Pantographs

[Ashley Hill]

Why did cross arm pantographs fall out of favour in the Uk?
Here’s a link to a photo by our own John W1 showing 86010 with a cross arm pantograph.

86010_1981_09_CreweA3_400dpi

Stabled at the south end of Crewe station waiting to take over from a diesel on a North Wales – Euston express on the 12th September 1981 is 86010. Locomotive History 86010 was originally E3104 and was built by Doncaster Works, entering traffic in September 1965. It became 86010 in the 1973...

flic.kr

 

[Flying Snail]

Because better designs took precedence.

Are cross-arm types used anywhere on any modern stock?

 

[SuspectUsual]

Why Do UK Trains Generally Have Single Arm Pantographs?

As in, not like many European designs like this: Is it just the diamond version is just an old design?

www.railforums.co.uk

Had an idea this had been discussed before!

 

[Ken H]

Why did cross arm pantographs fall out of favour in the Uk?
Here’s a link to a photo by our own John W1 showing 86010 with a cross arm pantograph.

86010_1981_09_CreweA3_400dpi

Stabled at the south end of Crewe station waiting to take over from a diesel on a North Wales – Euston express on the 12th September 1981 is 86010. Locomotive History 86010 was originally E3104 and was built by Doncaster Works, entering traffic in September 1965. It became 86010 in the 1973...

flic.kr

They were quite common till Brecknell Willis brought out their HiSpeed pantograph. That had lots of fancy stuff, like little aerofoils to make it have similar charicterisics in either direction, so the > shape was acceptable.

 

[AndrewE]

Why did cross arm pantographs fall out of favour in the Uk?
Here’s a link to a photo by our own John W1 showing 86010 with a cross arm pantograph.

86010_1981_09_CreweA3_400dpi

Stabled at the south end of Crewe station waiting to take over from a diesel on a North Wales – Euston express on the 12th September 1981 is 86010. Locomotive History 86010 was originally E3104 and was built by Doncaster Works, entering traffic in September 1965. It became 86010 in the 1973...

flic.kr

my guess would be that as train speeds increased above 100mph the mass of the whole scissors mechanism made the pan collector less able to respond to varying wire height and to follow it closely enough [without excessive spring pressure and upward force]. A bit like unsprung weight on axles having an unwanted effect on the track.

 

[Strathclyder]

When did cross-arm pantographs disappear off the UK network entirely in favour of the single-arms? As in, last loco/unit to carry one?

 

[Magdalia]

They were quite common till Brecknell Willis brought out their HiSpeed pantograph.

The older discussion mentions the intermediate stage with the Stone Faively pantograph.

There were some Greater Anglia class 317s that ran with Stone Faiveleys until withdrawal in summer 2022.

The only class 317s that got Brecknell Willis pantographs were the Stansted class 317/7s and the GN units 317337-348.

 

[Ken H]

The older discussion mentions the intermediate stage with the Stone Faively pantograph.

There were some Greater Anglia class 317s that ran with Stone Faiveleys until withdrawal in summer 2022.

The only class 317s that got Brecknell Willis pantographs were the Stansted class 317/7s and the GN units 317337-348.

q for all. but what AC Emus had cross arm pantographs? 309?

 

[contrex]

my guess would be that as train speeds increased above 100mph the mass of the whole scissors mechanism made the pan collector less able to respond to varying wire height and to follow it closely enough [without excessive spring pressure and upward force]. A bit like unsprung weight on axles having an unwanted effect on the track.

The films of the SNCF record run by CC 7107 reaching 206 mph in 1955 showed things getting pretty sparky and I gather the track and OHLE needed a lot of fettling afterwards.

Still captured at 9m 37s

 

[Ashley Hill]

Why Do UK Trains Generally Have Single Arm Pantographs?

As in, not like many European designs like this: Is it just the diamond version is just an old design?

www.railforums.co.uk

Had an idea this had been discussed before!

Thanks for this. I tried a search but this never came up.
So the main reasons seem to be to allow an increase speed and better contact with the contact wire with the Z style pan. The 81-85s appear to have had Z pantographs from new, would there have been a reason for fitting what appears to be the inferior cross arm pan to the 86/87s?

 

[SuspectUsual]

The 81-85s appear to have had Z pantographs from new, would there have been a reason for fitting what appears to be the inferior cross arm pan to the 86/87s?

I don’t think they had Z shape pantographs; they were a more simple two arm design

Photo here for example - https://flic.kr/p/d1Tvg3

 

[Ashley Hill]

I don’t think they had Z shape pantographs; they were a more simple two arm design

Photo here for example - https://flic.kr/p/d1Tvg3

Sorry, yes thats the type I meant. <

 

[D6130]

There's quite

q for all. but what AC Emus had cross arm pantographs? 309?

None....as far as I'm aware. The early dc EMUs - such as the 506s....and 306s before their conversion from dc to ac - had diamond frame pantographs, but they were a different kettle of fish altogether. The 309s had Faiveley pantographs - like all contemporary BR ac locos and multiple units as built.

Incidentally, all Trenitalia electric locomotives - except for the E403s - still have diamond frame pantographs (FS Type 52).

 

[contrex]

There's quite

None....as far as I'm aware. The early dc EMUs - such as the 506s....and 306s before their conversion from dc to ac - had diamond frame pantographs, but they were a different kettle of fish altogether. The 309s had Faiveley pantographs - like all contemporary BR ac locos and multiple units as built.

Incidentally, all Trenitalia electric locomotives - except for the E403s - still have diamond frame pantographs (FS Type 52).

I remember as a boy photos in 'train books' of the Shenfield units with the pantos extended quite high:

 

[Ken H]

I remember as a boy photos in 'train books' of the Shenfield units with the pantos extended quite high:

View attachment 188363

Love the buffers and drawgear.

 

[43096]

Incidentally, all Trenitalia electric locomotives - except for the E403s - still have diamond frame pantographs (FS Type 52).

I assume you are excluding E405, E412 and E494 locos?

 

[Taunton]

Thanks for this. I tried a search but this never came up.
So the main reasons seem to be to allow an increase speed and better contact with the contact wire with the Z style pan. The 81-85s appear to have had Z pantographs from new, would there have been a reason for fitting what appears to be the inferior cross arm pan to the 86/87s?

I don't think we can say "inferior". The 81-85 had two single-arm pantographs, and used the trailing one in each direction. The cross arm was just one, used both ways. I guess it is just normal product development from experience.

For whatever reason DC systems seemed to stick with diamond double arm pantographs long after AC systems moved on to single arm.

 

[contrex]

Love the buffers and drawgear.

A proper EMU, like the 4-SUBs.

 

[Davester50]

From an aesthetic pov, for me, the modern high speed Brecknell Willis ones look sleek. The box ones in the original aren't bad, but the chunky single arm ones look awful. Very top heavy, and dated.

 

[43096]

I don't think we can say "inferior". The 81-85 had two single-arm pantographs, and used the trailing one in each direction. The cross arm was just one, used both ways. I guess it is just normal product development from experience.

81-85 had two pans up until they were air brake fitted at which point they lost one pan to allow air tanks to be fitted. 86s only ever had one pan and they mostly had single arm pantographs, so your argument about both directions running doesn’t apply.

 

[edwin_m]

I don't think we can say "inferior". The 81-85 had two single-arm pantographs, and used the trailing one in each direction. The cross arm was just one, used both ways. I guess it is just normal product development from experience.

For whatever reason DC systems seemed to stick with diamond double arm pantographs long after AC systems moved on to single arm.

If I recall correctly, when they were fitted with air brakes they were reduced to one pantograph, with the brake reservoirs going where the other one had been. I don't know if the single pan was one of the original ones or a new one of whatever type.

 

[Bikeman78]

The films of the SNCF record run by CC 7107 reaching 206 mph in 1955 showed things getting pretty sparky and I gather the track and OHLE needed a lot of fettling afterwards.

Still captured at 9m 37s

View attachment 188344

Having had many rides behind the similar NS class 1300, I find this astonishing. They were always rather sedate.

The last train I can recall riding on with a cross arm pantograph is a Belgian classic EMU. Units built up to 1965 had cross arm pantographs. They finished in October 2013. Newer units and locos had Stone Faiveley (or something that looks very much like them) single arm pantographs.

 

[D6130]

Having had many rides behind the similar NS class 1300, I find this astonishing. They were always rather sedate.

The last train I can recall riding on with a cross arm pantograph is a Belgian classic EMU. Units built up to 1965 had cross arm pantographs. They finished in October 2013. Newer units and locos had Stone Faiveley (or something that looks very much like them) single arm pantographs.

I think those Belgian units had diamond-frame, rather than cross-arm pantographs.

 

[Bikeman78]

I think those Belgian units had diamond-frame, rather than cross-arm pantographs.

Yes, my mistake. In which case I have never seen a train with a cross arm pantograph.

 

[Taunton]

81-85 had two pans up until they were air brake fitted at which point they lost one pan to allow air tanks to be fitted. 86s only ever had one pan and they mostly had single arm pantographs, so your argument about both directions running doesn’t apply.

I believe the air brakes were not installed in 81-85 until 1971-73, effectively as part of the WCML Glasgow electrification project, by which time pantograph technology had moved on, particularly the aerodynamics of the upper wide part of the arm. I don't know whether the aerofoils were added to existing units, or new ones were installed. The single pantograph obviously introduced a new Single Point of Failure which needed careful evaluation.

 

[Ashley Hill]

I don't think we can say "inferior". The 81-85 had two single-arm pantographs, and used the trailing one in each direction. The cross arm was just one, used both ways. I guess it is just normal product development from experience.

I use the term inferior as the single arm pan was already proven so wonder why the 86/87s were built with the cross arms.
I understand there was a belief at the time that running “elbow first” would result in less damage to the OHLE and pan.

 

[43096]

I believe the air brakes were not installed in 81-85 until 1971-73, effectively as part of the WCML Glasgow electrification project, by which time pantograph technology had moved on, particularly the aerodynamics of the upper wide part of the arm. I don't know whether the aerofoils were added to existing units, or new ones were installed.

Did they get any change to the pans at all when they were air braked? Don't forget the 86s mostly had single-arm pantographs from new and they only ever had one pan.

The single pantograph obviously introduced a new Single Point of Failure which needed careful evaluation.

I think the "single point of failure" is very much over-blown with pantographs - most of the time if the pan gets a defect, it's going to pull the wires down, so the second pan is irrelevant!

 

[nw1]

Why did cross arm pantographs fall out of favour in the Uk?
Here’s a link to a photo by our own John W1 showing 86010 with a cross arm pantograph.

86010_1981_09_CreweA3_400dpi

Stabled at the south end of Crewe station waiting to take over from a diesel on a North Wales – Euston express on the 12th September 1981 is 86010. Locomotive History 86010 was originally E3104 and was built by Doncaster Works, entering traffic in September 1965. It became 86010 in the 1973...

flic.kr

I seem to remember they were mostly or even completely gone by late 1983/1984 on the WCML including on the 86s.
I'm not sure I've ever seen one, though it's possible I did on my first visits to the WCML in late 1982/early 1983 before I started taking real notice of the pantographs.

 

[43096]

I seem to remember they were mostly or even completely gone by late 1983/1984 on the WCML including on the 86s.
I'm not sure I've ever seen one, though it's possible I did on my first visits to the WCML in late 1982/early 1983 before I started taking real notice of the pantographs.

It was the May 1984 timetable change that ultimately saw off the cross-arm pantographs, as that started the 110mph era on West Coast that saw all the 87s upgraded with new Brecknell-Willis high-speed pans to replace the cross-arms they had from new. Some 86s also got BW pans, which presumably saw the handful of 86s with cross-arms converted to single arm.

I suspect the last locos to use the cross-arm pans were the three Class 82s and 83s retained for Euston empty stock workings (82008, 83009/015), all of which had cross-arm pans fitted.

 

[62484GlenLyon]

86316, at least, still had a cross arm pan in early 1985. It was one of the locos involved in working Hertfordshire Railtour's Great Eastern Pullman tour on 2nd February. I attach a rather poor picture of the loco at London's Liverpool Street station showing (just about) the cross arm pan.