P2 Locomotive Company and related matters

Dare I ask what's the matter with a booster? Surely one of these would be a unique feature.... plus getting heavy trains away from rest, sharpish..... if a new P1 ever were to be built.

 

Nothing wrong with the booster at all, I just think 2393 looked neater without the pipework runs... In fact I'd say that alongside the P2s, the P1s looked the most imposing of all Gresley's designs. The proportions look just right to me. I doubt if a booster would ever be needed though in the modern age, the loco's T.E should be well up to almost any job thrown at it. Recreating the booster would also entail quite a bit of extra expense in cylinder block casting, machining etc., and probably some re-design to improve the original booster I would have thought...

Richard.

 

Who said it is much better than other class 8 locos? I know of several runs with Canadian pacific where it turned in sub 30 gallons per mile. And that certainly had a fair gap between the chimney and the steam you could see too.
Lets not believe they have re invented the wheel.......

 

The linkages to the booster constantly broke and the thing could generally start the length of train the system could cope with = no need.
Best to try it something that needs it , like a Bulleid Pacific .
Not got a lot going for it other than Utter Magnificence. bit Big and heavy for Heritage, and even with a better front end it wouldn't be allowed over 60mph
Plus its massive nominal tractive effort would trump the P2

 

What was name of said driver and can one read more?

 

We will never know. But if he ever maintained that he did, given his unusual record, I would not disbelieve the claim, however unlikely, out of hand. The short travel A1s were no slouches when well handled though the maximum on record for the P1 was 65mph on something of a test passenger run while the P2 was being developed.
The P1 was, in some ways, more unfortunate than the P2. It had more haulage capacity than could be used but was built too early for anyone to realise that the design could be developed into something much more than a machine to handle slow, heavy freight.
Even though little in the way of improvement/development occurred with these two rather neglected orphans the view held by one of the best drivers to see service on the Eastern that they were superior to the much later standard type is, in its own way, illuminating.

 

If someone has a desperate need, and the money, to build something with a booster then a C9 is the obvious choice, even if no-one can work out what their wheel arrangement was. (4-4-4 or 4-4-4-4?)

 

Interesting point of view. From RCTS Part 6B:

Putting this into context, when withdrawn they had a worse adhesive factor than all of the Thompson and Bulleid Pacifics despite having an additional set of driving wheels.

So the advantage of a Mikado over a Pacific - the adhesive factor - seems to have eluded the P1s in some respects, except when fitted with a booster.

 

Is that partly a simplistic calculation though? The factor of adhesion calculation makes the assumption that the point at which slipping occurs is proportional only to the total weight on the wheels, and has no relationship to the contact area (which must be affected by both the number of driving wheels and the diameter of the wheels. Sadly I lack the expertise to judge whether that's reasonable. We shouldn't miss, of course, that the axle loading is much reduced with 8 driving wheels over 6, which must affect route availability.

 

I think there is something wrong with that calculation too. If the factor of adhesion is the total weight on the driving wheels divided by the TE, it is just a detail of the design. Other things being equal, an eight coupled locomotive should start a heavier train than a six coupled. The total weight on the drivers is more relevant. There are also other variables that will affect the propensity to slip.

 

One neglected advantage of later wide firebox boilers where several feet of combustion chamber was incorporated -to get better combustion/ a/s ratios, is that they also moved the centre of gravity of the boiler forwards, putting more of the weight on driving/ less on trailing wheels. Suppose if you were building one now you'd use the most evolved boiler to that profile ie an A4 /107

 

I was just reporting what has been written - granted I made an observation based on that. Common sense would dictate that a Mikado should have more adhesive weight than a Pacific.

Where the weight is distributed is, I suggest, a big part of the issue. The later A3 and A4 boilers were built differently to the original A10 boilers (despite filling the same overall footprint, they are very different beasts in some respects, including plate thickness). So when fitted with a different boiler and the booster removed, it is to be expected the performance characteristics of the P1s might be changed. Albeit, unexpectedly to me and everyone else, reducing the factor of adhesion substantially.

I rather think if they had proved successful there would have been more of them built. The commonality of parts with the Gresley O2 (valve gear) and the A1s/A10s/A3s would have been in their favour. Gresley built two, they never did the work well that was asked of them, the infrastructure was simply not there for the trains they were supposed to pull in the first place (100 wagon lengths requiring lots of marshalling) and when all is said and done they also had more restricted range due to the tender, lesser performance with the valve gear (original style Gresley valve gear without long travel)...

They were handsome locomotives. But I remain doubtful they were really needed on a railway full of 2-8-0 types.

 

They weren't, as you point out. The idea of running two trains in one had much appeal, but the restrictions to which trains of this length were subjected made them impractical. Besides the issue that they would not fit inside the lay-by sidings to allow faster traffic to pass, you also have to consider the drawgear on the wagons. The risk of a coupling or drawbar failure increased exponentially with the length of the train, and I remember reading that ninety wagons was the absolute limit for security.

The P1s, to me, shared many attributes of the later 9Fs, amongst which was that both were before their time, Really, neither was at home on the normal, unfitted goods; their worth would have been shown on higher speed, fully fitted, block workings. The 9Fs were a bit early for these, which mostly were given to diesels on their introduction, while the P1s were in a different era altogether.

The p1s were a failure, not because of any fundamental problem with the locos, but simply because their intended work wasn't possible within the existing conditions. Having proved that point, they were then redundant, and any need for further units patently did not exist.

 

The engines were not really necessary but were interesting. The LNE was aware of the problems that had to be faced integrating slow, largely unfitted, freight with the need to run increasingly quicker passenger trains. The company found that the K3 was a very good freight locomotive. No difficulty was found in hauling 1,600 tons and restarting it on a 1 in 400. And this was a faster machine than existing 2-8-0 types. increasing freight speeds was the way forward and this was going to become more pressing as the years went by.
If we observe modern guidelines then the P1 would have easily have become a 90mph+ type. Perhaps more importantly it would have exhibited the much improved acceleration capabilities so needed today.

 

Cleveland Bridge has produced this video:

Foxy

 

roller bearing big end is fitted to the P&M Panther 600 "Sloper " single . a popular sidecar machine . good for breaking legs if it "kicked"back

 

...and so it goes forward, the first wheelset has been completed by South Devon Railway Engineering who are getting quite a reputation for this sort of work....

https://www.p2steam.com/2017/08/23/first-wheelset-assembled-no-2007/


Foxy

 

One bump per lamp post, Cleckheaton's finest.

 

I'm just looking at the prefab. cylinder 3D CAD sketch on the P2 website. Looks as though piston valves have replaced the poppet valves originally proposed.

I hope this is not the case.


Sent from my Nexus 7 using Tapatalk

 

Definitely not. Remember that the P2 has Lentz valve gear, not Caprotti. Totally different beast in terms of valve layout.