Current and Proposed New-Builds

And given that we've already got most of the bits... the only currently uncharted territory (aside from rear frame extensions and bogies) would be the cylinders and valve gear on the 3-cylinder variants. Building a 'K' or 'L2' surely can't be beyond the wit of man... and given that the 'U' and 'N' are well-proven types in preservation, it's not a massively risky leap in the dark, unlike, say, an LBSCR 'L' 4-6-4T (says a poster calling himself "BrightonBaltic"!).

 

I'd absolutely love to see a P1, in final condition with booster removed. I can't see the necessity for a booster on the modern railway, it's cheaper to build one without the booster (although in the scheme of things it will still be damned expensive of course), and there won't be the added reliability or upkeep problems of the flexible steam connections to the booster engine.
Looking at photos of them in action, I tend to agree with Bulleid, that they were Gresley's finest-looking locos. Absolute brutes!

Richard.

 

Duplicate post - deleted.

 

Did the P1's have the same valvegear as the A3's? i.e limited to 65% cut-off which gave the problems with starting.

If there was any situation these days that needed a booster, you would just have a Diesel on the back.

 

If I get chance, I'll have a look at Clay & Cliffe's "The LNER 2-8-2 & 2-6-2 classes", see if that gives any gen.

Richard.

 

RCTS says short travel valve gear and 75% cutoff.

 

Surely one of the huge benefits of having that booster would be obviating the need for the diseasel on the back even in leaf-fall season?

The tender booster wasn't a new idea even on the P1, pretty sure Gresley got the idea from the old GNR Sturrock 0-6-0s.

 

From Wikipedia (so may be open to inaccuracies), but:

The P1 class engines were initially equipped with two-cylinder boosters attached to the trailing axle. These were engaged using a Westinghouse pump mounted on the boiler to engage the cylinder clutch. These had a tractive effort of 8,500 lbf (38 kN) when used, increasing the tractive effort of the locomotive from 38,500 to 47,000 lbf (171 to 209 kN). It was intended by Gresley these boosters would be used to assist the locomotive while starting and topping the banks over which they travelled.

The tenders equipped to the P1s had a specially-designed dragbox to accommodate this equipment. In practice, the boosters were troublesome; using them would fill the cab with steam, while the fireman's workload would be doubled. The steam pipes from the boiler to the booster were prone to fracture, particularly on the sharp curves of the turning triangle at New England shed. The boosters were removed from engines 2393 and 2394 in 1938 and 1937 respectively.

Richard.

 

The boosters were a source of unresolved issues, the flexible steam pipes required improved materials and some design modifications. These might have gone some way to solving the staff having problems not being able to judge how to tighten up the ball joints. It was a problem then, we could undoubtedly solve it now.

You would solve it because you could, but would you need to? The cylinder bore would be reduced to 19" to improve route availability, the effect on nominal tractive effort would be balanced by an increase in boiler working pressure. The original engines were fitted with the short travel valve gear fitted to the early O2s, they were never modified with the later long travel type but could still exceed 60mph. The later gear would make them far more free running particularly considering the 9" piston valves that go with A4 based cylinders. You are looking at a nominal T.E. in excess of 48,000ibf and the adhesive weight of the originals was only 71 tons 10 cwt at the most. A new build would probably be heavier but the factor of adhesion would still be a bit of a concern. That booster could be useful in limiting the tendency of the main engine to slip but no preserved line could make good use of the power of such an engine and as for the mainline we don't have platforms long enough to handle the number of coaches this thing could deal with as even a modest test of its abilities. That doesn't exclude me from wanting to have one tried out though!

 

Bet that using steel-braided Kevlar (or is it Teflon?) pipes like car brake hoses would sort that out. True that a tractive effort north of 47,000lb would tend to make the booster redundant, but in the autumn leaf-fall season it might be useful...

 

It's been discussed umpteen times before on the forum - one of the main reasons for having a diesel on the back on a railtour is operational flexibility (for example shunting at termini) where modern rationalised track layouts prevent such operations being made easily. You can have all the tractive effort in the world provided by a booster but it won't help if your destination has no run-round loop to release the loco on arrival.

Tom

 

Nor if the needle and water are falling away...

 

If you're talking mainline, I'm guessing you're still talking 'Diesel', booster or no booster.

Given the LNER Encyclopedia comments that valve gear was taken from Gresley's own earlier (pre-grouping) class O2 2-8-0, developed before the exchange trials which brought long-travel piston valves to the LNER, it's a pretty safe bet the P1 was saddled with short travel valves and (though you won't get me to say so on oath!) IIRC, I've seen a reference to them being so fitted.
https://www.lner.info/locos/P/p1.php

 

What would be the purpose of a new P1? Too powerful for heritage lines, drivers too small for useful mainline speeds. Needs bigger wheels - hang on - didn't Gresley design something a bit like that?

 

Given that heritage lines seem to rather like 9Fs, even the relatively flat NNR, the P1 isn't that big a step away, and while 3 cylinders means more maintenance, it also means a smoother ride, and the shorter coupled wheelbase is more curve-friendly.

Wrong. P1 would be in the 60mph class with the Halls, Black Fives etc. The S&C is 60mph limited, I believe, and there are many lines where if you can get up to 60mph quickly and maintain it, there are paths to be found. Plus, the P1 could haul significantly longer, heavier, more profitable trains.

 

The thing is, the 9Fs already exist; you don't have to build them. And most of their present work is within the capabilities of a Class 4.

 

Instead of the booster what a fireless which can be charged up en route and can then assist on banks and shunting

 

It isn’t the weight or length of trains that makes them more profitable, it’s how many paying passengers they hold. In other words, no point adding three extra coaches if you can’t find 150 extra passengers to fill them.

Tom

 

9f's exist, a do the other classes you quote. No one is going to fork out P2 type big money for a 60mph freight engine. Even less so for one that will only operate on heritage lines. Time will prove me right.

 

Wouldn't need to be P2 money given there are already spare A3 cylinders & boiler extant, would just need to negotiate their acquisition - even if you did build 100% new, it would still be a significantly attractive project. P1 would be a mainliner too, no reason not to. Also, a loco that can haul 15-coach trains enables you to spread the running cost over more passengers, so ticket prices can be lower, hence more sales, more people turn out... just need a suitable name to give it an identity that the public can identify with*

*and an engineering base secured before any project launch, etc etc, taken as read...