25kV stuff - old and new (and other electrics)

[Genghis]

Mick,

The APT power car brake was a Hydrokinetic brake mounted on the end of the motor shaft. The HK brakes on the ATP gave fabulous stopping performance. I was told that the drivers loved them. As their design - like any other dynamic retarder - relied on the speed difference between the rotor and stator to give torque, if the wheels started to lock up the torque was instantly reduced - a self sustaining wheel slide protection system. The downside was that braking effort reduced off as speed fell to zero (much like a electric dynamic brake before a solution was found). There were two significant problems with the HK brake. They were cast from an aluminium alloy which was prone to cavitation damage. Aluminium was used for weight saving as the brake was contained within the axle on the trailer cars. The major problem, which really killed the design, was ensuring the integrity of the axle which contained two rings of bolts to hold everything together. Once these started to fail there was an obvious safety hazard. Braking to rest was provided by tread brakes on the trailer cars. I cannot remember if the power cars had tread brakes (possible for wheel conditioning reasons) or if there was a small disc brake on the motor shaft.

A problem with putting a disc brake on a motor shaft is that the rotational speed is far higher than on a wheelset. The brakes are ventilated and act as fans. Unfortunately they also act as sirens. London Transport ordered some bogies from Kawasaki (shock, horror, questions in the House etc) which had motor mounted discs. When these were tested at Derby the noise was so great that the tests were abandoned until a revised design had been produced.

BR Research (me) had a project looking to see if we could use the power car brake on trailer cars driven by a gearbox. Not really cost effective but it did give me the chance of running some test trains on the WCML at 125mph. Motive power was either an 86/1 (which had the class 87 bogies) or an 87. They were able to sustain 125 mph running well, but the train formation was rather short. Labs 15 and 21 (ex HST caterers converted to an instrumentation coach and test car) plus ex Glasgow- Edinburgh disc braked mark 2s. If you thought that the ride on a Mark 2 on the WCML at 110mph was interesting, you should try it at 125!

APT was also the first use of extruded aluminium as a material for forming bodyshells.

Dave

 

[Genghis]

Probably a bit of a dim question but does anyone know, if class 91 are generally superior to class 90, why some 91s have been withdrawn and yet some container trains are class 90 dual-hauled?
Great explanation Mickoo. Always interested to hear more.

Using a 91 on container trains would be like trying to use a greyhound on a dog sleigh.

You can do it but you'd be better off with a husky. 91's were designed to be 140mph passenger locos and have traction characteristics to match. The 90's were always intended as mixed traffic locos.

 

[simond]

David,

you remind me of the LT steerable bogie, which, I thought was a BREL design. I took over the disc project at Lucas Girling from Steve Gaskain, after I’d spent a couple of years in Cwmbran developing car brakes and lab test systems.

My recollections of the disc were that it was mounted on the end of the motor shaft away from the gear set. It was cast iron, 390 dia by about 100 thick, dual row ventilated, with an in-cast steel bell to allow for expansion, and was heavy.

The actuator / adjuster was very novel, I had much less to do with that. I think Colin Tickle designed it.

 

[Genghis]

I think Colin Tickle designed it.

An excellent engineer and a steam lover. Driver on the Welshpool I think?

 

[Genghis]

Just found some photos: APT power cars had tread brakes.

 

[mickoo]

A problem with putting a disc brake on a motor shaft is that the rotational speed is far higher than on a wheelset. The brakes are ventilated and act as fans. Unfortunately they also act as sirens.

Dave

Reminds me of my first introduction into AC motor drives with Holec, their party (demonstration) piece being a pre-loaded software into the drive that could make the motor sing, in this case the national anthem. We've probably all heard modern EMU stock singing as it accelerates, but to hear 1.1Mw crane motors sing the national anthem is quite something else.

It did however have a serious side, there are certain frequencies in AC motors that will result in their destruction rather rapidly, those frequencies are locked out in the drive electronics and 'stepped past', as are those that are uncomfortable to people traveling on the train or at stations. On cranes we only stepped past the destructive ones, the others I can assure are very painful after long term exposure during fault finding.

 

[Genghis]

And of course on trains the control system is designed to step past frequencies that might irritate the signalling system!

 

[New Haven Neil]

Somewhere up near Carlisle...can't be more accurate than that, sorry! I'd say about 1987 or so.

 

[New Haven Neil]

Taken on an all line Railrover in 1976. This loco seemed to be everywhere we went under the wires, with its distinctive yellow 'arrows of indecision'.

 

[simond]

An excellent engineer and a steam lover. Driver on the Welshpool I think?

I believe so, I think he may have also been their Chief Engineer at one point but I lost touch when I moved on in the late 80's

He also had an exquisite collection of 3.5" gauge live steamers - I recall a 28xx and a 4-6-0, perhaps a King but it's a very long time ago. I think he had a third one too. They were exceptional models.

Just to return to the motor-shaft mounted brake-disc, the noise calculations I did for that one suggested a max overspeed through a tube station would cause injury due to the noise - the issue being the very limited clearance between the circumference of the disc and the axle, effectively closing and opening each ventilation passage in turn, a sort of rather inefficient siren. The other problem was that the pumping losses of the discs were excessive - it simply absorbed greater & greater percentages of the motor power in pumping air through the ventilation slots as the speed increased - it was very early days for computational fluid dynamics (and despite the work I did on 2S engines for my thesis, I don't think I was very good at it either) but we did improve the pumping losses whilst still getting the brake heat out of the disc - It was a fascinating project, which took me to Brush on a couple of occasions, and to Golders Green depot every Tuesday for about 18 months to inspect the one trial vehicle that was running in a Northern line set. The shed foreman would look up when I arrived, say "oh bloody hell, it's you again, hang on I'll find out where it is", followed by a few minutes on the phone, and "go and get a cuppa, it'll be here in about three quarters of an hour". Every week for about 18 months...

And we had the excitement of the burst rig too - a device to allow overspeeding of the brake disc to the point where it would actually fail through centrifugal loading. A big steel tube embedded in a very large lump of concrete, and arranged so that we could partially evacuate it to reduce the ever present pumping loss issue. And a big motor, and lots of pulleys and toothed belts and so on. A bit Heath Robinson!

The steerable bogie itself was a smart thing too - and the driver for mounting the brake on the axle-hung motor - there really wasn't anywhere else to put it! Sadly, the projected savings in track and wheel wear were not sufficient to justify the cost and complexity. I guess that' what prototypes are for.

thanks for prompting the reminisicences

atb
Simon

 

[Brian T]

I have don't have too many pictures of electric locos and the quality is some what lacking and being a teenager at the time i did'nt really know any different!!.
Anyhow hope these are of interest to you all...there's also a couple of E5001 too if you need some DC deviation.....

My only class 81 pic,
81012 sat in Euston about 1988

next few are at Stafford a favorite haunt when i was younger.....
85037.

86404 double heading another container train...

and 90041

Lastly 90033 stabled at Wolverhampton High Level,this i think was the very 90's..

Brian.

 

[adrian]

My only photo of the APT was taken at Crewe Works open day in 1981.

I didn't think I'd have anything to contribute, no outstanding images carefully composed - just a "snap" when I was young spotting APT at Carlisle - unfortunately I can't remember the date, in addition to this one I also have a few more of of APT at York IIRC - will have to dig through my collection.

 

[mickoo]

Some earlier B&W, I do need to revisit these and re scan better.

Starting on the SR with some ED's, the first two at Victoria on Gatwick Expresses in the early days when they carried target set numbers






Another ED at Waterloo.



Moving to the ER, first Kings X,



Then Liverpool Street



Then on to Manor Park which was my commute station to Maryland whilst at college in West Ham, all early morning, which is odd as the platforms are bare and they were usually rammed with commuters; so I'm not commuting and any other early morning I'd be hung over....mind that feeling also accounted for many commute mornings too it has to be said. It's bitterly cold and there's a sharp frost on the platforms.









Finally a shot between Maryland and Forest Gate, I'd have been on the express going home and the 315 is heading into London so this'd be a Friday evening ride home with a 47 up front. We've just cleared the Stratford/Maryland restriction and the driver is winding the old girl up and it'll probably be Ilford by the time we get up to max speed depending on the passenger loading, I seem to recall most of these early evening trains were standing room only.

 

[76043]

I remember those GE electrics, lots of variety at that time, almost crazy amount of variety considering now there's only 720's and 345's doing those jobs, with the dull Stadler units now on the Norwich run. That last 315 has the four position route indicator over the second man's window, a short lived feature I recall.

In those days I recall being able to catch a jaffa cake 309 into London from Romford and being very impressed with the ride.

Seats on everything but the 315's were also luxurious, something that I miss now we just effectively get a beach towel draped over a plastic chair these days. Seemingly nothing to do with fire safety but saving money.
Tony

 

[Richard Gawler]

The class 312 sets continued to provide the 07:32 and 08:02 departures from Hatfield Peverel until 2004. The view from the window was always that bit better than from the low floor stock. Withdrawal came early because of a lack of central door locking.

In those days you could see quite a few generations of stock - Mk1 catering vehicles, other Mk2 and Mk3 loco-hauled stock, and for a short while EMU classes 312, 321 and 360 all on the same day.

 

[Lancastrian]

Saturday 10th April 1982.

86 233 "Laurence Olivier", Euston Station.


96 205 "City of Lancaster", Euston Station.


85 034, Cockshute, Stoke.


Tuesday 10th August 1982.

87 030 "Black Douglas", Manchester Piccadilly.


81 004, Crewe Station.

 

[Lancastrian]

Tuesday 31st August 1982.

Manchester Piccadilly Station

86 xxx


83 001


Crewe Station

86 210 "City of Edinburgh"


85 002




86 217 "Comet"


87 024 "Lord of the Isles"


86 211 "City of Milton Keynes".....which wasn't, but now is!


86 221 "Vesta"


Ian

 

[Lancastrian]

Tuesday 14th June 1983. It's amazing how rubbish some of these prints are. I need to look at a new film scanner at some point.

Preston Station.

81 006


85 012 and 47 049


87 032 "Kenilworth"


86 039


87 035 "Robert Burns"


87 019 "Sir WInston Churchill"


Ian

 

[Lancastrian]

Friday 6th August 1983

Preston Station

86 239 "L.S. Lowry"



85 01x


86 231


85 024


Saturday 20th August 1983

BREL Crewe Works

86 035


81 016. (Edited after Mickoo's post below.)


Preston Station

Unidentified Class 81


Ian

 

[mickoo]

The last image is an 81, smooth body sides and square base to the body, 85 has inset section where windows are to allow whole upper mid section of the body to be lifted off like 86 and 87, they also have a rounded base to body side. Class 81 is the only class to have square base of the body, all others are rounded.

Given the corrosion marks on the front I might be able to come up with a number....Addendum, almost certainly 81 012 which has an identical rust spot at the top of the LH handrail where it's been welded and two marks below the head code, reference photo is dated 25th Aug 83 but copyright so can't really post here (but for those that are on FB and may be able to see the link Facebook) and the first three coaches (all 1st class + brake) are identical. So may well even be the same train, the odds of three 1st class at the head end is quite small and it's deemed to be a special working from the south passing on the through roads at Crewe. The date also fits in very closely with other photos posted up here.

Crash damage is also an 81, in this case 81 016 and the accident was in Dec 82 at Linslade tunnel. The train derailed inside the tunnel on a northbound sleeper service and then collided with the bridge abutment just outside; the driver was killed but the second man who was driving survived with a broken right shoulder. Recent photos of the crash site and from inside the cab the morning after have recently surfaced on the FB page, sobering is the word I'd use. One hopes that in the pitch black (02:02 time of collision) the driver never saw the bridge abutment before impact.

Whilst at Crewe and during organised works visits, people were asked not to take photos but people did anyway, the real rub came on open days when it was parked outside and people allowed to climb all over it, that generated some resentment from people at the time. I think it languished at Crewe for four years in that state before finally being disposed of.

RAIB report.

https://www.railwaysarchive.co.uk/documents/DoT_Linslade1982.pdf