The AC Electrics: Classes 80-85, 86, 87

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Inversnecky

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I’d be interested to learn more about the history and development of the ‘AC Electrics’.

As I understand it, there was one prototype, a Class 80, which developed into Classes 81-85. These then led to the 86, then the 87.

What were the principle design differences between them, performance and reliability?

‘Cosmetically’, the 81-85 look very similar: the 86 has a less slanting front, and the 87 was the first to be designed without an integral headcode (also distinguished by two instead of three windows).

I look forward to some knowledgeable comments from those who familiar with them.
 

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randyrippley

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80 was a converted gas turbine loco used for driver training and load bank testing because deliveries of 81-85 were running late

81-85 were competing prototypes / technology demonstrators using differing combinations of builders and parts

86 was the main production build

87 was a a follow-on order of 86, uprated with new bogies and cosmetic changes

90 was intended as a second batch of 87, but was heavily modified with a new body shell and further uprated

81/2/3/5/6/7 are all stressed skin steel construction
84 had a massive steel solebar with glass fibre non-structural body

86 was unique in having bogie mounted unsprung traction motors - a change which destroyed the track
 
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Richard Scott

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Not wishing to go off topic but there were numerous 3000V DC versions of the 83 built for Poland, many are still in use. The EU06 was built by English Electric with the EU/EP07 and EP08 built in Poland. Would be interesting to know how much these had in common with the 83? Obviously no transformer or rectifiers.
 

Gag Halfrunt

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From Wikipedia:

EU06 locomotives are roughly similar to the British Rail Class 83 mechanically, which were built by English Electric at Vulcan Foundry, Newton-le-Willows in the UK, in the same period; electrically the layout and equipment was similar to classes 5E/5E1/6E/6E1 operating on South African Railways.

 

Inversnecky

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The topic inspired by discussion here:

https://www.railforums.co.uk/threads/class-28-“loaf”-metro-vick-type-2-co-bo.213986/page-3

@6Gman and others commented on mercury then silicon rectifiers, and informally ordered their reliability thus, in declining order:

85
81
82
83
84

Numbers produced, built, last year withdrawn:

80 - 1 prototype, built 1951, rebuilt 1958, w/d 1968

81 - 25, 1959-64, 1991

82 - 10, 1960-62, 1987

83 - 15, 1960-62, 1989

84 - 10, 1960-61, 1980

85 - 40, 1961-64, 1992

86 - 100, built 1965-66, still in service

87 - 36, 1973-75, 2007
 
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43096

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84 had a massive steel solebar with glass fibre non-structural body
Do you have a source for that, as I can find no mention of it?

The AC Loco Group (https://www.aclocogroup.co.uk/index.php/history-introduction/class-history-al4-84) says this, with no mention of glass fibre bodies:
The Corten steel locomotive body and the paint system used by NBL appears to have caused problems throughout the AL4s life, with large patches of paint frequently falling off the locomotive body.
 

Inversnecky

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The AC Loco Group (https://www.aclocogroup.co.uk/index.php/history-introduction/class-history-al4-84) says this, with no mention of glass fibre bodies:
Didn’t see that site when looking for info, thanks for posting it. Will have a read.

As a youth, I don’t think I ever encountered these: in the north of Scotland, none of the lines were (or indeed still are) electrified: it might only have been attached at Glasgow to sleepers taken to London on a few 1970s visits, but I don’t know.

(If a diesel took a sleeper train from Inverness, would it have tended to continue all the way to London, or did they tend to replace with with ACs for the rest of the way on the E/WCML?)
 

43096

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Didn’t see that site when looking for info, thanks for posting it. Will have a read.

As a youth, I don’t think I ever encountered these: in the north of Scotland, none of the lines were (or indeed still are) electrified: it might only have been attached at Glasgow to sleepers taken to London on a few 1970s visits, but I don’t know.

(If a diesel took a sleeper train from Inverness, would it have tended to continue all the way to London, or did they tend to replace with with ACs for the rest of the way on the E/WCML?)
The West Coast sleepers used to change locos at Mossend or, in more recent times, Edinburgh to switch to an electric loco for the run south. This continues to this day with the Highland Sleeper being Class 92 hauled south of Edinburgh.
 
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What were the differences in the 3 Class 86 subclasses, as I knew them back in the 70s and 80s?

86/0
86/1 - only three of them
86/2 - the electric equivalent of a Duff to me.

And, of course 87 101 was unique. Was it originally 87 036?
 

CW2

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Didn’t see that site when looking for info, thanks for posting it. Will have a read.

As a youth, I don’t think I ever encountered these: in the north of Scotland, none of the lines were (or indeed still are) electrified: it might only have been attached at Glasgow to sleepers taken to London on a few 1970s visits, but I don’t know.

(If a diesel took a sleeper train from Inverness, would it have tended to continue all the way to London, or did they tend to replace with with ACs for the rest of the way on the E/WCML?)
Depends whether you mean early or late 1970s. The WCML electrification was completed in 1974. Before that it would have been electric north of Crewe - and later north of Preston once Crewe - Preston was electrified. The standard loco on the WCML (north) was the class 50, but those seldom worked north of Perth because of traction knowledge issues.

Back on the original topic, the class 81 - 84 were stored en masse once the fragility of their mercury arc rectifier systems became obvious. With the class 86s having been built there were many more locos available than there was traffic for them to haul (prior to electrification through to Scotland), so they 81 - 84s were all laid up for conversion. I recall going on a trip to Euston station one Sunday and seeing about a quarter of the entire class 86 fleet simply parked in a row. Likewise in the early 70s visits to Crewe Works and various Manchester and Liverpool depots found assorted locos sitting around waiting for their call to works for conversion.
What were the differences in the 3 Class 86 subclasses, as I knew them back in the 70s and 80s?

86/0
86/1 - only three of them
86/2 - the electric equivalent of a Duff to me.

And, of course 87 101 was unique. Was it originally 87 036?
86/0 were 86s as originally built, with their original track-destroying suspension. Initially 100 mph, subsequently downrated to 80 mph and restricted to freight work.
86/1 were prototype 87s, with flexicoil suspension, but retaining dual brakes. 110 mph.
86/2 were 86/0s with flexicoil suspension. 100 / 110 mph.

I think 87101 was originally intended to be 87036 but never ran as such. The different number made traincrews aware of the different driving techniques necessary, and also highlighted the fact it was different as there were concerns it might cause signalling interference.
 

Helvellyn

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What were the differences in the 3 Class 86 subclasses, as I knew them back in the 70s and 80s?

86/0
86/1 - only three of them
86/2 - the electric equivalent of a Duff to me.

And, of course 87 101 was unique. Was it originally 87 036?
  • 86/0 had AEI 282BZ traction motors. Original design bogies so by the 1970s limited to 80mph to mitigate the amount of track damage from the unsprung weight of the traction motors on the bogies. Also fitted with the same multiple working equipment as used on the Class 87s. Originally 48 locos but 86040-86048 were converted to Class 86/2 (86253-86261).
  • 86/1 had GEC G412AZ traction motors and new bogies as eventually used on the Class 87/0s (these were effectively prototypes).
  • 86/2 had AEI 282AZ traction motors. Modified with flexicoil suspension, i.e. large springs connecting the bogie and body. Allowed to operate at 100mph.

20 86/0s were modified in the early 1980s into 86/3s by the use of SAB resilient wheels - the wheel was in two sections separated by a rubber bearing. This allowed the maximum speed to be raised back to 100mph. (86010-86029 became 86310-86329).

In the late 1980s all the Class 86/0s and 86/3s were modified with the same flexicoil suspension as used on the Class 86/2s and thus became Class 86/4 (86401-86439).

There will be various other details that people will add but two other sub-classes from BR days:
  • 86/5 - 8 Class 86/2 locos were modified for freight use with ETH isolated and the maximum speed reduced to 75mph. This was only for a short period from 1988 and I think all were renumbered back to Class 86/2 1990/91.
  • 86/6 - Railfreight Distribution modified its Class 86/4 locos by isolating the ETH and reducing the maximum speed to 75mph. 30 locos were modified.
 

43096

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  • 86/0 had AEI 282BZ traction motors. Original design bogies so by the 1970s limited to 80mph to mitigate the amount of track damage from the unsprung weight of the traction motors on the bogies. Also fitted with the same multiple working equipment as used on the Class 87s. Originally 48 locos but 86040-86048 were converted to Class 86/2 (86253-86261).
  • 86/2 had AEI 282AZ traction motors. Modified with flexicoil suspension, i.e. large springs connecting the bogie and body. Allowed to operate at 100mph.
I thought the motors were the other way round: AEI 282AZ on the 86/0 fleet with AEI 282BZ on the 86/2s?
 

Taunton

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81-85 were competing prototypes / technology demonstrators using differing combinations of builders and parts
I wouldn't exactly call them demonstrators, as 100 locos were pretty much the bulk of the fleet needed for the initial electrification. But it was BR policy at the time to go out to multiple suppliers, and while this was a nonsense with 5 separate builders and designs for the about 20 diesel railbuses, it seems more appropriate for the first AC locos with what was then a very new and fast-developing technology. Notably the several suppliers of the electrical gear (the key new bit) were the same set of mainstream organisations as were installing equipment in the various AC EMUs.

Someone centrally at BR must have done a detailed drawing of what they were to look like, as they are pretty indistinguishable from one another, although the actual body construction techniques to achieve this differed.

The difficult part was the rectifier; Class 81-84 had mercury ones, like the pioneering SNCF AC locos had done. The majority of the Class 85 were built with solid state germanium rectifiers. Germanium is an element somewhat similar to silicon, and starting to point the way, but it is rare and expensive, whereas silicon, the most common element of all, had been developed to be used in the last 10 of Class 85.

The rebuilding of the locos in the early 1970s, a number of which were stored, put 1970s-generation silicon rectifiers into all these earlier ones. Whereupon it appeared that they were not the sole source of trouble, and Class 82 and 84 in particular were soon all stored again. I don't know what the subsequent issues were, apart from the 84s being inevitably the North British design.

There were some early sub-classes as well, which seem forgotten nowadays; the last five locos numerically, E3096-3100, were variants of the other ones, with different gearing for freight. Initially numbered E3301-05, they hardly seem to have been used as such (or even photographed), and they soon got regeared to be the same as the others and renumbered at the end of the series.

Someone wrote in Modern Railways, in about 1990 when the Class 90 were being introduced, that for the same rectifying function as Class 81-84 had, with a huge reinforced mercury tank that required an overhead crane to lift in and out of the loco (and goodness knows how much all that liquid mercury cost), the equivalent function in the Class 90 was done by equipment the size of two baked beans cans!

Never forget that the 1960s IBM guidance computer for the Apollo spaceshot to the moon had less processing power than a current iPhone. The world moves on!
 

Inversnecky

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Looking at photographs, I was intrigued to come across an image of an 86 with a rhomboid pantograph: I thought the Woodhead 1.5kV DC 506/76 were the only BR trains with that type of panto?
 

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Richard Scott

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Looking at photographs, I was intrigued to come across an image of an 86 with a rhomboid pantograph: I thought the Woodhead 1.5kV DC 506/76 were the only BR trains with that type of panto?
If you look at the 87 in second picture that one also has one. Have seen other pictures of 87s with that type of pantograph.
 

Inversnecky

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Also, why did they change the shape of the cab ends when the transition was made from the 81-84 to the 85/86 (i.e. from a continuous slope to a flattened vertical).

Was there visibility issues?

Anyone here who drove them who might know about that aspect?
 

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CW2

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Back in 1980 I fetched up at Glasgow Central one Sunday afternoon to find 84003 at the head of the 1515 to Nottingham. 84s on passenger were practically unheard of at the time, such was their epic unreliability. I hadn't had one for 7 years previously. We arrived at Carlisle on time, having come down Beattock at 104 mph, but with the loco having cut out several times en route. An alternative loco was found for the return working to Glasgow Central and the 84 hauled off to Kingmoor for (more) repairs.

I think at one stage there was a mercury arc rectifier from a class 84 (?) on display at the NRM. I don't know if it is still there.
 

Taunton

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Looking at photographs, I was intrigued to come across an image of an 86 with a rhomboid pantograph: I thought the Woodhead 1.5kV DC 506/76 were the only BR trains with that type of panto?
It's not quite a simple rhombus shape as on Woodhead locos, but what was known as a "crossarm" pantograph, as the lower half components cross over. They were used for a while.
 

43096

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It's not quite a simple rhombus shape as on Woodhead locos, but what was known as a "crossarm" pantograph, as the lower half components cross over. They were used for a while.
A number of 86s (about 10?) were fitted with the crossarm type rather than the standard Stone Faiveley. I think the 87s were all built with the crossarm type, but all received replacement Brecknell Willis high-speed pantographs from 1984 when the first 110mph workings started.
 

pdeaves

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Not wishing to go off topic but there were numerous 3000V DC versions of the 83 built for Poland, many are still in use. The EU06 was built by English Electric with the EU/EP07 and EP08 built in Poland. Would be interesting to know how much these had in common with the 83? Obviously no transformer or rectifiers.
The Poles painted on in pseudo-BR livery, see https://www.flickr.com/photos/warren_wordsworth/2300467108 (not my pic!).
 

Mag_seven

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I think the 87s were all built with the crossarm type, but all received replacement Brecknell Willis high-speed pantographs from 1984 when the first 110mph workings started.

87009 ran around with a Stone Faiveley type for a while:

(photo by "Jamerail" on Flickr)


87009 speeds through Nuneaton station on a Northbound passenger service. Unsure of exact date, but sometime in week 4th-8th July 1983.
 

jfollows

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There's a book called the A C Electrics I remember seeing at one time, but can't recall publisher etc:
Colin J. Marsden, OPC/An Imprint of Ian Allan Publishing, 2007 ISBN (10) 0 86093 614 7 & (13) 978 0 86093 614 5, 128 pages, lots of pictures. I've got a better book with more technical detail somewhere if I can find it ......
 
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Elecman

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It’s amazing how different that looks, very continental!

Slightly OT, but doesn’t deserve a thread on its own: what causes the clicking you hear on electric lines, as heard hear at 3:58 -

The air reservoir pressure valve?
 

CW2

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To that book list you can add:
The Power of the AC Electrics, Brian Morrison, OPC. ISBN 0-86093-246-X. (1988) Hardback, mostly black & white photos, but also some technical details and line drawings.
British Rail Fleet Survey 6: Electric Locomotives. Brian Haresnape, Ian Allan. ISBN 0 7110 13322. (1983). Softback. A chapter for each class of AC locos then in existence (i.e. predates classes 89/90/91/92). Includes DC classes 71 - 77. Good selection of photos and technical insights.
 

Inversnecky

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Interesting to see a signal box apparently in Intercity livery!

0:57 in:

 

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