Sir Nigel Gresley - The L.N.E.R.’s First C.M.E.

And results with five significant figures.
Then it must be true.

 

I'm aware of that - and therefore why IC125 was so successful, even where the 125mph capability wasn't used.

It's an interesting question - but also betrays our experience in a multiple unit railway, where the labour costs of turning and coupling have largely been eliminated. One wonders whether that cost would have registered in Gresley's era?

 

So. theoretically, how much difference to achieved speed does,say, 10 miles of 1 in 256 falling make relative to Level, all else constant?

 

And, if none, what difference does that make to coal consumption (and therefore cost)?

 

I think one of the really big savings is the reduction in signalling complexity needed by EMUs. That's both a capital and ongoing revenue saving.

If you can get hold of a copy, see if you can get the two South Western Circle volumes on signalling at Waterloo. They show just how complex the signalling (and associated track layout) was in the steam era. Consider a mainline train arriving and being prepared for subsequent departure:

- Train arrives
- Pilot engine comes in
- Pilot draws carriages away to carriage stabling point (which in the case of Waterloo, was 4 miles away)
- Train engine departs for loco servicing point

- Pilot engine draws mainline stock back into station
- Train engine comes onto stock
- Train departs
- Pilot departs for stabling

That's eight moves to enable a simple in and out; with a modern EMU it would be two, with the train serviced in the platform. (Even if you go away for servicing it is only four, and with simpler track work by eliminating the loco servicing point). That is not only conducive to higher availability of the carriages (i.e. more time in revenue service); but all those unremunerative moves still had to be signalled, and all that signalling paraphernalia had to be maintained and operated.

Playing devil's advocate (just to upset @S.A.C. Martin : Could you make a case that Gresley was tactically brilliant at getting a much improved high-speed performance by considering the whole train; and strategically awful in not realising the future was electric and multiple units ...

OK, I'm being mischievous - but I'd suggest Maunsell showed the way to the modern railway to a far greater extent than Gresley did. The 4-CORs were introduced about the same time as the Silver Jubilee, and kept going for years afterwards; and moreover were replaced by things that were fundamentally evolutions, not departures. I think you could make a strong case that Southern strategy under Maunsell was the beginnings of the modern world, whereas LNER strategy under Gresley was wringing the last possible development out of the old: the A4 is like trying to sell a piston engined fighter in 1947. Fast, but ...

Tom

 

Trying to remember my G T Moody, but wasn't it really Herbert Walker calling the shots on the Southern? And didn't the Brighton Line come first with the 6 PANs? And was it Raworth who was responsible for the traction equipment?

 

Yes to all those … But inasmuch as cross-railway strategy gets ascribed to one name …

The key point is see though was that the SR, to a far greater extent than the LNER, were following a strategy that had far-reaching implications and pointed to the future: not just on odd bits of line, but across major swathes of their territory. You might even say there was demonstrable influence on other railway engineers and managers

(And in my view, Walker was the pre-eminent railway manager of the twentieth century, bar none).

Tom

 

I wasn't going to go there, though I quite like the idea that Maunsell was the radical and Bulleid the stuck in the mud I also remember Waterloo when it throbbed to the sound of Cromptons & Hoovers, you could walk up the cab road, and there were sidings north of the Windsor Line platforms...

However, and staying on topic, I do wonder about the recognition of shunting costs at that time. Being serious, for something like the Silver Jubilee, would the additional workload associated with turning the Beavertail have even registered?

I'm interested in this from the perspective of what was driving decision making. Much of the conversation on this thread has been about outright performance levels as a driver, rather than anything to do with cost. Yet we know that coal consumption was an important economic variable for railways, so it's then interesting to know what view was taken of terminal operations and the costs associated with it. Given the immaturity of activity based costing models at that time (see debates about the traffic survey before the Beeching Report), I genuinely wonder whether those costs would have been considered?

 

But to be fair to others we mustn't forget that the Southern was by far in the best position for electrification. Its telling, I think, that nearly a hundred years on so many of the LMS, GWR and LNER lines still aren't electrified, but the majority of the Southern is.

 

So with respect to Tom, I am afraid I can't support his views (though it gave me a chuckle!)

With the main reason being that Gresley was looking forward to the future with technology that would ultimately supersede the third rail system on the Southern.



So DC, rather than AC, but close! Gresley was much enthused by the development of No.6000 and overhead electrification was something he had been keeping an eye on for some time. The problem was capital costs, and third rail was cheaper to do than overheads, but (given my experience working on the Southern, Anglia and Eastern Regions of the network) the third rail system has actually stifled development in the southern region, and caused huge issues of mismatches across the mainlines. 25kV overheads is interoperable with Europe and has proven its worth time and again.

Our issue as a nation is being somehow unable to continue the knitting project to project and mainline to mainline. Of course, without Tory cuts, the whole of the GWR might be electrified, and the Brighton mainline might have become the next big project towards joining up the overheads. (but that's a by the by)

There's no doubt in my mind that Gresley was abundantly right to go from steam to electric without much care for diesel traction, and (had he lived longer) I suspect his full systems development - bearing in mind he was working on:

• streamlining the trains
• improving the signalling systems (A4s had in cab signalling pre war on test, sadly abandoned)
• improving the braking systems of the high speed trains
• looking to electrification of the LNER main lines

...would have been one of the world's first true high speed mainline railways. He was so close. Quite frankly, Gresley really was onto the basic principles of today's high speed railways, particularly in the design of the streamlined trains.

The A4s and the streamlined trains give us a real taste of "what if" but, of course, the war put paid to it all.

 

Today's engineers working on it would also say how much they hate it. Third rail is truly dangerous at ground level and really restricts working lineside. Not just my view but that of many rail engineers.

That doesn't mean I am not fond of it, mind - having commuted using the Dartford loop lines for many years. But 25kV was, and is still, far superior. The issues are always capital costs and trade offs. It is telling that third rail has been non preferred technology for over twenty years, though.

 

Worth remembering that decades before that LNER overhead electric loco illustrated, the LBSCR had started electrification towards Brighton with overhead AC - that really was the future. So a handful of DC electric locos built in 1941 hardly marks Gresley out as a trendsetter in respect of overhead electric. It's an interesting "what if" as to why third rail came to be chosen as the standard on the Southern Railway rather than overhead, but once chosen, the SR then built out at scale. I'd suggest that in electrification, it's hard to make a case that Gresley was either an innovative harbinger of the future (as in the LBSCR system) nor pushing it forward at scale (as Walker subsequently did on the SR).



Tom

 

If we're focusing on Gresley's lifetime, AC electrification was not on the agenda - the technological shift for that to be used at scale was post war, hence Woodhead being an island rather than the precursor of a national rollout. The overhead/3rd rail question belongs elsewhere, but I agree with @Jamessquared that the SR and constituents deserve the real credit for focusing on main line electrification as the basis for long term development.

I would also be interested to know just how far Gresley's involvement extended with the Woodhead electrification - I have always had the impression, fairly or not, that electrification was a peripheral matter and not high on his priorities, so assume it was delegated.

 

The LBSCR - and German electrification was AC from the start

 

As an example. A 400ton train of Mk1 carriages travelling at 70mph.

The Draw Bar Horse Power DBHP ( i.e. the power exerted in hauling the carriages ) can simplistically be
split as Work Done against Resistance WDAR and Work done against Gravity ( i.e climbing a gradient WDAG

( steam age calc using Imperial units, apologies if some of this is obvious but I am trying to answer the
question from first principles. I am also limiting it to the carriage stock. Actually DBHP is the useful
figure as far as traffic management is concerned. EDHP and IHP tell us more about how the loco is
performing and of course how much energy is used merely moving itself )

WDAR = m x R x V all divided by 550
where m = load in tons. R = resistance in lbs/ton and V is speed in ft/sec.
At 70 mph the BR Mk1 test figures gave R as 11.6.
One horsepower is the work required to lift 550lbs one foot in one second.

WDAR at 70mph = 400 x 11.6 x 102.7 divided by 550 = 866 HP

WDAG = m x V divided by 550 x gr
where m = load in lbs, V is speed in ft/sec and gr is the gradient

WDAG at 70mph = 400 x 2240 x 102.7 divided by 550 x 256.= 653 HP

The train is initially travelling on the level at 70mph with 400 ton consist.
The DBHP is WDAR ( there is no work against gravity ) i.e 866 HP

WHen the train joins the downhill gradient ( I feel the query has
Roundwood to Eastleigh in mind ) the loco has gravity in its favour I.e
653 HP.

An acceleration curve could be created ( and an equation to fit )
but simplistically there is now the equivalent of 1519 DBHP available.

At 88 mph on the level the WDAR with 400 tons is 1492 HP, allowing
for potential errors speed at the ten mile stretch of 1/256 (Shawford ? )
would be 88mph.

Michael Rowe

 

Thank you Michael. That's the kind of sum I was thinking of.

Actually I was thinking of Stoke Bank --maybe that is 1 in 264 ....

So maybe plug in a 70mph starting point, a 200 ton load, 126 mph after 10 miles and derive the required DBHP. Then predict the finishing speed on level ground.

From the discussion above, to do it properly an air resistance term would be needed to dampen the acceleration curve.

I've always wondered, thinking of Papyrus's 108 on level track and Mallard's 126, what the net difference is when you remove the gradient effect.

Peter

 

IIRC the streamlined ecs went out to a sheds between Hornsey and Wood Green. Hornsey turntable would have been nearby for the turning of the beaver tail.

 

Wasn't the NER electrification scheme (York-Newcastle?) planned to be 1500v DC overhead? Was this just economically related that it didn't proceed with on the creation of LNER? They built a prototype model EE1?

 

Yes - but then they went and spoilt it all by removing the whole lot. A big step backwards, actually.

 

Both low frequency systems though (25 Hz for the LBSC system, I believe). The useful thing with the German 16 2/3 Hz is that it allowed the use of universal motors without external rectifiers and without the efficiency being too terrible, at the cost of needing bigger transformers; I wouldn't be surprised if the LBSC system used similar hardware. Really robust rectifiers were definitely a thing of the semiconductor age, in locomotive terms.