Loco musings ex the 71000 thread

..... the fireman doesn't have to manually fire the oil, and you can develop higher / more consistent firebox temperatures as you don't need to open the firebox doors at all when running.

I'll get back to you ref ihp and TE

 

Sheff alluded to a couple of issues in his post, namely grate limit and fireman exhaustion. Another issue would perhaps be variable coal quality. With oil firing, the fuel is of a known controlled quality and can be burned at a constant rate for a sustained output. Yes, a stoker can provide a constant supply of coal, but, the grate limit is a ceiling on combustion, plus factors such as carry-over at high combustion rates are an issue.

The 5AT has a projected Tractive effort of 135.2 KN - which I think is around 30,000 lbf and a max indicated power of 2574 KW, which is around 3451 IHP.

These are figures pulled from the 5AT website:

http://5at.co.uk/

A fascinating and highly educational site, would dearly love to see this project happen

Cheers

Alan

 

Would be interesting to learn of where and which classes.

 

As the 5AT website is rather labyrinthine, here's a direct link to some of the predicted performance data ...... http://5at.co.uk/index.php/the-5at-locomotive/5at-performance.html

 

Thank you gentlemen, most enlightening and interesting reading.

If this ever does happen, it looks like 4771 would loose its moniker of the "pocket rocket"!

Interesting to note that some of the projected figures are based on hauling a 29 coach train.........................................

 

............... but not up Shap!!

BTW - I thought the pocket rocket was a Std 4 2-6-0 - you'd struggle to get a V2 in yer kecks

 

I kind of gathered that!..................................... though maybe be with a good run up...................................

Still impressive figures though.

One in each leg?.......................... oh, hang on there is only one!

(Project no.3 for the A1 trust, a V2 variant?...................................)

I for one have always known Green Arrow as the "Pocket Rocket", but then again I'm biased so I would say that wouldn't I

 

We really are a long way from 71000 now, but 5AT Group would be up for a light(er)weight 2-6-0 for secondary lines - eg the Cambrian. We can but dream ......

 

With what grate area? I really doubt it would be possible to build a loco within the UK loading gauge that was coal fired, hand fired and could sustain 4,000ihp - even the figure quote for a Duchess, which I think is about on the limit of that specification, was only a bit over 3,000hp for five minutes. Oil firing, or mechanical stoking, might help, but at what (financial) cost?

Anyway, you can't play "fantasy loco designer" unless you also play "fantasy service planner". So here is a little historical digression:

In the early 1930s, the CME of one of the "Big Four" (a bonus 'like' available for the first person to say who) drew up a scheme for a locomotive that would have been about 100 feet long. It would have had a tractive effort of about 50,000lbf; 6'3" driving wheels, 3,400 sq ft of heating surface, a grate area of 52 sq ft and weighed 209 tons.

The Civil Engineer agreed to the use of the loco on about 130 miles of the mainline outside London, with a maximum speed of 75mph. The CME and the Traffic Manager worked out a scheme in which ten such locomotives could replace 64 conventional locomotives (54 * class 5/6 passenger and mixed traffic 4-6-0s; 8 * class 4 mixed traffic 2-6-0s; 2 * class 3 goods 0-6-0s) provided the manufacturer could guarantee mileages of 140k - 160k between heavy overhauls - to which the manufacturer agreed, subject to the provision of a certain quantity of spares in addition to the order for ten locos.

Needless to say, the scheme never proceeded. The reason is fairly obvious - to have been feasible, it would have meant running a small number of very large trains. But the platforms at the major stations weren't long enough; the goods loops weren't long enough; the sidings weren't long enough; the draw gear on wagons may not have been strong enough. In the end, a greater number of smaller locos gave a more flexible service.

Which is simply to point out that maybe there is a reason why 4,000ihp locos didn't exist in Britain that goes beyond the "not invented here" or "it can't be done" arguments. Maybe there was simply never an operational need for such big locos?

Tom

 

I think the reason the 5AT style projects don't get support is the total moderness of the design just doesn't appeal to those who remember steam, it's just as alien as a 66, Tornado and all the other new builds or conversions are generally to traditional designs discreet modifications here and there, I'm not sure there's the appetite for something totally new as the 5AT or variant would be.

 

Would this be refering to Bulleid's proposed 4-8-2s? Or the Stanier Super Coronation? (I might have just made that last one up... apologies if so)

 

Nope ...

Tom

 

For a totally uneducated guess, it would be one o' them there CME's that like to O D on Brasso............................... so Collett then..............................................

 

Nope … Can you actually imagine Collett even thinking about a loco that deviated one iota from what Churchward had been building 30 years previously?

Tom

 

Yes David, that's why the project was shelved. Not enough people in the movement who are driven by the engineering challenge alone. Also it needed to be done properly, so would have needed a serious sponsor - eg Branson Rail. Maybe when all the traditionalists have shuffled off, and all the ex-BR locos are on their knees its day will come. I might see what we could do by way of a 'half way house' - ie incorporating as much of the technology as possible into an existing loco of which there are numerous - eg Black 5, Rebuilt West Country or similar.

 

I was just pulling........................ given your penchant for all things Southern - Maunsell! As Gresley was already playing with hush hush and p2's IIRC!

As for God's Worst, if you like O Ding on Brasso, ANYTHINGS possilble Lol!!

 

This above gets pretty close to the nub of the problem. High horsepower is needed for two reasons.

1) To shift a greater weight at moderate speed, or,

2) To move a lighter load at higher speed.

Item 1 is thwarted by line and siding capacity as Gresley found with the P1 2-8-2s of the 1920s. For item 2, is a machine with big heavy lumps of metal flailing about with varying degrees of balancing sitting directly on the track suitable for 150 mph capability? Answer no. Can such steam powered machines be built within the UK load gauge that are capable of consistently producing 5000 or more HP to run such trains, Answer again no.

Lets take the East Coast route as an example. A4 Pacific 2000 hp good for 70 to 80 mph. For 100 mph operation the 3300 hp 'Deltic' required. For 125 mph the HST with 4500 hp. The current electrics in operation on that route - 5000+ hp.

Much as we may like steam (and believe me, from my limited experience it is bloody hard work!), we have just got to recognise (5AT group notwithstanding) that the steam locomotive has come to the end of its development. Over the whole world this has been recognised.

 

Give that man a coconut. More after I've had my tea and put the children to bed!

Tom

 

You're living on dangerous ground there Sheff, as even when certain generations have past, there will still be "purists" to fly the flag, ie past down from father to son, or even daughter!

But I agree with your sentiments, One day it WILL be built regardless of what it looks like!