P2 discussion (split from train length reduction thread)

You could argue the same thing of the 9fs mind and they were entirely capable in the steam era.

The advantage of the P1 compared to an A3 or A4 is the superior adhesion factor. That was the issue with double heading on the Aberdeen line.

So why not try an existing mikado design on that route first?

In any event the line speed restrictions of the Aberdeen mainline were more onerous than that on the east coast mainline. So - just thinking out loud - would not testing the existing design have been better?

We will never know though.

 

The 9Fs and the P1s were different beasts completely and to try and compare them is pointless IMO. 9Fs were designed with, inter alia, fast freights in mind - e.g. the GC Windcutters - whereas the P1s were designed for low speed, extra heavy haulage in mind. As for the rest of your post, I'm sure the LNER traffic department knew what they were up to by not using the P1s on fast passenger workings.
In fact they wanted more P1s to replace 0-8-0s on heavy goods.

 

Hang on - they're not entirely different in one respect. Both were designed specifically for goods traffic and the 9F is - accepted - much more of a freight locomotive than the P1. It had 5ft drivers for a start, so the slightly larger drivers of the P1 are a fair comparison.

The entire point of the P1 design - including the booster fitted example - was to speed up the longest and heaviest freight traffic (100 wagons potentially on a P1 hauled train). The fact they were under-utilised because the extra long heavy freights didn't materialise in traffic requirements is a moot point when considering their potential. If they were capable of pulling these extra heavy freight trains then experimenting with using them on the workings on the Aberdeen route would have been interesting.

Neither the 9F nor the P1 was built for passenger traffic: but the P1 is clearly more suited to it - slightly larger driving wheels (5ft compared to 5ft 2in) and a front pony and rear cartazzi. It shares a great deal of its genesis with the A1s and had the same free steaming boiler. Both members of the P1 class were fitted with A3 boilers towards the end of their lives when their original boilers became life expired, so they were also continually developed in some ways alongside their A1 and A3 cousins.

I don't doubt they wanted P1s to replace 0-8-0s on heavy goods: but the P1's design looks to me to be exactly what Gresley needed on the Aberdeen route. If the later 9Fs can be trusted with express passenger workings, why couldn't the clearly more suited P1s have been also?

 

The P1s were to speed up goods - mineral - traffic by combining two trains into one, not by increasing the average speed per train over the road. The idea failed because the 100+ wagon trains could not be accommodated in the lay-by sidings, so any following traffic was bottled up behind. The P1s did everything expected of them, but that did not include even medium speed fitted goods.

 

You can try as much as you like to make a case for the P1s on the Aberdeen route but I'll trust they guys on the ground who were around at the time. "In 1934, No 2394 was experimentally tried on the 07.45am semi-fast from New England to Kings Cross as part of the planning stage for P2 class locomotive 2001 Cock o' the North. Although the engine was able to reach a maximum speed of 65 mph, this put too much stress on the fireman who later commented that he was thankful not to have been going beyond Peterborough."

 

Given how long some of the freights spent waiting around in loops, that would have been very wishful thinking by the traffic department.

 

There's no way, for example, the P2 could visit the NYMR (or at least, not long stretches of it) as some of the curves tested Tornado when she visited and the extra length of the P2 wheelbase means it's very unlikely to fit round their curves. In this day and age where Network Rail look to make curves less tight and lines straighter where possible, there's some advantages there.

That's not what David Elliott told me when I asked him a while back. He was of the opinion that the P2 would be able to go anywhere the A1 could - and as for Tornado being tested by the curves, it has now run on the NYMR on several visits and does not seem to present any more problems that 60007 and the other A4s that have run on the NYMR do. Without checking I can't honestly say whether their wheelbase is shorter than the A1, but I think that probably the important dimension is the distance between the rear driving axle and the Cartazzi truck axle.

 

As far as I know, although the P1s may have received A3 boilers late in life they never got long travel valves like the A3s (and modified A1s). I imagine getting a small wheeled P1 up to 65mph might not have been the wide-open regulator and short cut-off performance associated with later Gresley pacifics. Given that the major shortcoming of the A1 as built was a healthy appetite for coal, I'm not surprised the fireman was a bit busy.

The 9F, which keeps on coming up in comparison, had rather more enlightened valve events, hence their capability for surprising speed.

Edit to add: None of this is to say that A3-type (or maybe even A4-type) cylinders and valve gear couldn't have been fitted, and perhaps it's a shame it wasn't. The result could have been a much more versatile machine.

 

Correct. As mentioned by anther poster, one of the problems with the P1s is that the freight trains for which they designed could be a major operational problem. Add to this that the 100 wagon freights became few and far between - by 1932 only one a day remained - and their raison d'être had all but disappeared.

 

Yes, the problem in a nutshell. But since these trains couldn't use the sidings, then the objective of speeding up the goods service might well have been achieved.

But the passenger service, on the other hand...

 

My thoughts exactly. Well put. I should add that the A1 became less coal heavy as its valve events and travel valves were improved as a result of the 1925 exchange with the GWR.

If the P1s had been developed in parallel in that matter they'd have been intriguing machines probably as capable in many respects as the A1s.

But - as with the A3s - improved draughtiness would have changed that position. And 65mph is pretty good going for a locomotive you say isn't up to pulling passenger trains! Remind me of the average speed restrictions on the Aberdeen line?

Much lower than the East Coast main line at the time as it happens. So it is the highest top speed or - as the P2s proved and a P1 might have done too - the ability to keep a train going and to accelerate it quickly might be of more use.

I can't believe the booster fitted P1 wouldn't have had admirable performance on a much lighter passenger train? Smaller driving wheels, we are always told, helps with acceleration and more coupled wheels equals more adhesion. Add a booster and you have a lot of power, superb adhesion - what's not to like and be intrigued by with that?

Interesting - happy to be corrected. I asked Mr Elliott that very same question but it was a number of years back. Times have changed and things have moved on perhaps

 

As the proposed Gresley 4-8-2 would have had a wheelbase only 6" shorter than a 9F, I wonder how he would have addressed the flange issue. I suspect with all wheels fully flanged which in turn makes me wonder if the absence of flanges on the centre axle of the 9F was really necessary. Could it have been purely to allow for colliery and other industrial locations? Would anyone be brave enough to re-tyre the centre wheels of one of the surviving 9Fs and see how it ran? Probably not, but a computer simulation could be interesting.

 

The real answer to speeding up goods would come with fully fitted trains but for the majority of goods services, that was many years into the future. By 1932 only one 100 wagon train remained on the New England - Ferme Park and the LNER turned its focus to speeding up the shorter coal trains with K3 Moguls.

 

You misinterpret. Being "up to" and being "suitable" are two different things. Just because the P1 reached 65 mph it does not mean it would have been suitable to running these speeds day in/day out.
Trials showed the booster was only really effective on loads of at least 1600 tons and doubled the fireman's workload. Hardly a glowing recommendation for their continued use on lighter passenger trains.
I still say that the traffic department, shed masters, crews etc. knew far more about what a P1 was best suited to than any of us on here. Not even your beloved Edward Thompson tried them out on the Edinburgh - Aberdeen route so why criticise Gresley but not ET for this "oversight?"

 

I really don't understand why you think the P1 wouldn't have been in any way suitable for passenger traffic. Least of all the Aberdeen traffic which - again - would have had more speed restrictions in place than on the East Coast mainline. We basically all agree the locomotive is capable of pulling some exceptionally heavy loads: so why not lighter loads with better acceleration almost guaranteed due to the smaller driving wheels and more number of them compared to the Pacifics.

Many of the passenger tank engines across the country employed in day to day service had similarly sized driving wheels and the Stanier 8F had smaller wheels than the P1, and I don't believe anyone would state they were incapable or unsuitable for passenger traffic?

Just what is it precisely about a P1 that wouldn't have made it usable on passenger traffic? Come on now, just because it's a freight engine primarily doesn't mean it wouldn't have been capable of dealing with passenger traffic.

It's hardly radically different to a Gresley A1 - everything above the running plate is virtually identical to a Gresley A1 with some detail differences in the super heating and snifting valves at various times of the locos lives. The valve gear is very close to the later V2 and the cartazzi arrangement is virtually identical to the A1. The only difference is the pony truck and eight driving wheels - the latter is an advantage in many respects.

I'm not denying that but with the same modifications that the A1s received when they were modified to A3s, they might have been more capable than otherwise thought. What exactly is it about the P1 that would make it unsuitable?

I did actually criticise Thompson and Peppercorn also, if you read what I said.

You always seem to attack me personally for my views on Thompson despite on many occasions actually misquoting me or misunderstanding my view. Not to mention he was barely mentioned except to say he virtually ignored them (which I lament).

Could you maybe take off your Gresley fanatic cap and be a bit more objective and less personal in your posts? Or is your intention to make every post you make - even the good ones - an ad hominen argument with little basis in fact?

 

It was not a personal attack so do leave off please and I am not wearing a "Gresley fanatic cap," I just find it amusing that you seem to know more about the P1s and their capabilities than the guys who actually had to deal with them.

 

I find it amusing you can't tell the difference between hypothetical comparisons. I've asked you several direct questions and you resort to being unpleasant rather than answering them.

This isn't the first time on this forum and it really is wearying.

So once again - given the above, could you give exact reasons other than a sketchy "because the shed staff said so" answer to the question of why these engines couldn't have been suitable for passenger work? I'm not saying masters of their craft - but again, if a Stanier 8F with smaller wheels can do it, why not a P1?

 

Absolutely true, but that was only one third of the problem. The lack of continuous brakes limited goods train speeds to a point where they could be stopped within signal sighting distances, and this low speed allowed the use of short-wheelbase wagons, whose riding qualities were suspect at higher speeds; and allowed axlebox bearings of lower quality, and hot boxes were far from uncommon even at these reduced speeds. To raise goods train speeds required all three issues to be tackled, and given the size of the wagon fleet, would have been massively expensive. Hence the drive to find a cheaper alternative.

But we seemed to have wandered slightly off topic (again!).

 

Perhaps they should have called it P1/P2 thread. In as much as theP2's weren't altogether suited to the peculiar task they we're given, im not convinced that the P1'S would have been much better, Pros - even more starting grunt and a slightly shorter coupled wheelbase ( and even then 1 and a half feet longer than the minimum necessary) than a P2 Cons low top speed and inefficient at sustained high speeds. That's not to say that had the P1 been trialled some interesting lessons might have been learned the Hypothetical P3 being a larger Mikado version of the V4 Perhaps. Wait for it the 9f 's were intended to be heavy freight movers with a Top speed of 50mph.. end of. Their high speed capabilities being as a result of using standard components/ designs from a proposed fast freight (Standard 2-8-2) and a realised mixed traffic design (Britannia/Clan) without alteration. Thanks to a lot of attention to detail in many areas they are superbly versatile locomotives