Atomic Systems

i just saw this pic and thought the emu looked quite familiar the emu in the pic is a 4 pep which was a prototype emu in the sr



regards david

Was'nt that the prototype for the 507/508's ?
I seem to remember it being at strawberry hill for years.

yeah i think so

regards david

The PEPs were prototypes for all of BRs "next generation" MK3 EMU designs. And like all next generation prototypes the engineers and managers at BR who had certain ideas about how things were done, particularly in the southern region where they were chosen to go through trails, found them a bit too radical and a bit too costly for their liking. So out went ideas of traction motors on every axel (imagine your stopper to Surbiton accelerating like a rocket) and things like Scharfenberg couplers which are only beginning to be seen today. So basically what you got out of the PEPs was bits of this and bits of that being applied incoherently being applied to all of the future EMU designs from the 455s to the 319s.

The next time a next generation design came around in the form of the Networker they tried to get it right and come up with a design that would act as a generic blueprint for all future EMU designs and yet again thanks to entrenched ideology and commercial expediency they managed to come up with another failure.

As Lord Alycidon of Welwyn has noted: BR Procurement always rewarded 'conservatism' over innovation. Maybe in some areas that has been wise, but in others it meant we've lost out. To an extent, we're fortunate that Derby RTC did have the guts to look at design from a fresh starting point, the alternative would have been to stagnate train design with the Mark 1 - which was simply a development of Big Four coaches. Maybe in the future, some more of the wacky ideas of the RTC may return.

As for Networkers, no doubt BR Procurement had something to say about them - like the song of the bird: "cheap cheap" - and I reckon that with a bit more money per unit, they would have come good. The Wabtec refurbed 465s aren't bad, though. Networkers have, ironically, been the 'generic blueprint' for future Multiple-Units: The Turbostar/Electrostar/Juniper families are all decendants of the Advanced Suburban Train!

Elojikal wrote:The PEPs were prototypes for all of BRs "next generation" MK3 EMU designs. .

Depends what you mean by prototype. The PEP units were very different to the Mk3 units in construction and technical design, although from a passenger perspective they have similarities (but there again the LNER and LMS were building sliding door steel bodied electric stock before the War which had similar features and layout to the 1980's class 455). They were aluminium bodied and as you pointed out had two outer motor cars with smaller motors on each axle, giving 8 motors per unit. The 313/4/5/507/8 units were the production run and carried these features forward, but with detail design differences. Although they could be seen as a prototype for a new way (at least for the Southern routes) of working inner urban commuter services, technically they are very different to the 317/455 family, which are steel bodied and only have one motor coach per unit with four motorised axles, partly according to reports in various books as a result of the old Southern Region taking a dislike to the idea of aluminium bodied multi-power car units. As such the Mk3 derived units, constructionally and electrically, are an integrally-constructed development of the Mk1 family which were steel built with single motor cars, although obviously different in passenger design and the use of modern electronic control.

It's sobering to note that today the former Southern is being run using substantial numbers of aluminium bodied multi-power car units, and to that extent the cheaper, "simpler" Mk3 derived units have become the dead end, not necessarily the PEP derived units. Of course, steel bodied, sliding door, open saloon electric inner suburban units were operating on the LMS before the war and the LNER had a design ready to commence services out of Liverpool St in 1949, so in that respect the Southern could be accused of being overly cautious in unit design and development. By contrast, the PEP family units could be seen as being ahead of their time, at least for Britain's railways, in being some of the first production aluminium bodied trains to enter widespread service, and their use of multiple motored axles to maintain high acceleration and performance.

One minor point is that the PEP units actually had three sets of doors per side (on the driving cars the "driver's" door could be used by passengers) whereas the production units had only two, which was carried on in the 455 and most subsequent designs. Also, it's said that the PEP sloping cab front, which didn't get used on the production units, was the basis for the cab front of the Northern Irish 80 Class Mk2 DEMU, minus the recessed corridor front door!