L1 new build

Looking at successful smaller wheeled tanks, there is, as you say, the N7 at 4ft 10in and also the numerous GWR panniers at the even smaller dia. of 4ft 7.5in
I'd say that as with industrial small wheeled locos the key success factor was the use of inside cylinders, which give a much reduced racking effect on the boxes, as you can visualise. Each piston thrust is taken by both boxes, rather then the box on the side of the outside cylinder under load acting similar to a pivot point.

But then there's always the 9F to disprove just about any theory, running up to 90 mph on passenger trains with their 5ft drivers. Two factors come to mind - firstly they had five driven axles so more boxes to to share the loads, and also they were a thoroughly modern design, so boxes and lubrication possibly superior to the L1?

What's odd about the L1 is that it appears to largely a K1 Tank, and I don't recall the K1's being any worse than a B1 in terms of box wear, and 62005 performs sterling service to this day. So unless Thompson changed the box design for the L1, I'm not sure where you'd start with your modified design, unless you went the whole hog and used canon roller bearing boxes. (Having just had a dig in the library I discovered that according to E S Beavor, one reason the L1's were rough was the elimination of axlebox wedges by Thompson - but again would this not apply equally to B1's and K1's?)

 

Prussian Railway Class T18 (DB/DR Class 78)

I spent a day on the footplate of 078 246 from Rottweil shed on a diesel diagram, in 1974. We kept time easily, and were 3 minutes early on arrival back at Rottweil at the end of the diagram.

On the home run the driver had a bet with the fireman (a university student on vacation work) that he could get the boiler pressure down to below 12 atmospheres (15 working pressure) by vigourous acceleration from the numerous station stops. The fireman won a crate of beer, despite our early arrival.

 

Just remembered something about the L1s regarding their axlebox issues. I vaguely remember reading somewhere that the outside cylinder small wheeled design, which naturally will lead to a lot of movement and strain in the frames and suchlike, rattled the side tanks to pieces, which then leaked and this was an important part of the issue with the axleboxes - water. I'm very open to corrections though.

 

So specific questions for Stuart Readers: Where are you planning on building this?

 

Why I think maybe not be a good idea having so many new build now, I think a L1 is quite a good one in that A. It good for heritage line use, B. was a design which as far as I know had many driver aids fitted, and D. would be quite cheep engine to build compared to say the Gresely V1/3 as it only has two cylinders and possibly have parts used on the preseved K1 and B1 types. However it needs proper leadership direction and a regular income source not just a Facebook group. Hopefully the axle box problom won't be such a problom. funny the same axle boxes were in use on the K1s and B1s maybe the fact it had water tanks made a diffrence?

 

we are still in the early stages and are currently sourcing a base for the locomotive

thanks

 

I suppose it's a case of catch 22....

 

Yes your right. Also its where is good for the engineering aspect side. And although the loco groups are separate as such, having a large heritage railway next to you does make more local people join. The lms patriot does have many members who join because that's where were based. 82045 benefits from being at the svr. It gets huge amounts of people able to see their progress. And they benefit from the svr raffle from time to time.

I know it can be done with out a home as such. But I would recommend any newbuild to try to get a home with good engineering facilities. And preferably one that has a large number of visitors.

Gav

 

That will be just one SVRA raffle at present Gav - not from `time to time`!

 

Sorry I thought you had and two so far. My mistake.

But you can't deny the fact that being at the svr helps. Makes people believe in the project because of its location.

 

We run a smaller raffle ourselves each year, perhaps that is what you were thinking of.

Certainly our location helps but it was hard work in the early days getting anyone to take us seriously. Success breeds success and the decision to start building from the bottom upwards has proved to be a sound one. It also means that we do not have parts lying around waiting to be fitted - quite honestly there is no space at Bridgnorth to use as storage. People/ supporters believe in it now because it is there for all to see and they can also see our dedicated `Monday gang` working on 82045 each week. We are of course lucky to have a skilled and semi skilled team who give their time and talents voluntarily.

We are currently fund raising for our wheels of course - any help out there?

 

In practice the L1's knocked themselves to pieces because the thrust loads were too great for the axleboxes and because they were required to run too fast. Sure the wheel size isn't the only consideration. Had they been three cylinder they might have got away with the small wheels, or larger wheels with the two cylinders, but the combination of relatively small wheels and two large cylinders was too much for the mechanical design. You say 6.2" is OK for 100, but actually that speed would only be attained briefly and rarely. If it had been a regular occurance then there would have been the same sort of problems. The L1's in outer suburban service were freqently required to run at 60+ and they couldn't sustain it without disastrous effects on their maintenance. The LMS and BR 2-6-4T's had no such problems.

The battering effect of the L1's were so great they were constantly going back to shops for the tanks to be repaired. It's unlikely the tank leaks led to the axlebox deterioration, because the vibration would have to be already there to split the tanks in the first place. I don't know why the K1's didn't suffer - you'd need to know more about the detailed design than I do to answer that. Maybe the longer wheelbase had something to do with it? Tanks can roll about a lot more than equivalent tender engines - perhaps that got the wear cycle started and then things went rapidly downhill?

There _shouldn't_ be anything wrong with three cylinders for starting, in fact they _ought_ to be better - no risk of being stuck on dead centre and more even torque (smaller peaks on the tourque mean less provocation for the slip to start, although its true there is less peak tractive effort - but the mean tractive effort is really what you want). It admittedly is more complicated with the Gresleys and unrebuilt Bullieds because the theoretical torque and the actual torque could be quite different! Steam engines are empirical enough that what is theoretically right sometimes doesn't work out in practice.

I accept most of these things are academic from the point of a loco on a 25mph preserved line, but the reputation of the L1's is going to count against them when trying to raise funds.

 

I know, I know. Most people hate the appearance of the Thompson pacifics. And I do wear glasses But I'd still like a model of one of the A2/2's for my layout. (Or maybe I should start a website for a new build? We could use a lot of Tornado bits... >

I think making the L1 even more powerful will only make things worse!

 

Woah! - you've crossed a line there MrTwoPigs

 

It won't let me just do a :razz: back so I'll just do a big

 

we still want to build a L1 tank, obviously we will be doing reasearch into this before any money is transfered to the group.
we are looking for people who are interested in joining to email the project at L1locogroup@live.co.uk, and give some contact details for when membership starts. BUT this wont start until we find out IF full drawings survive, as with out drawings we have no basis for project.nothing is confirmed yet but we will be seeing if it is possible to build one capable of running at LOW speeds, 25mph.

 

I can recommend the Folkestone Harbour Branch. Excellent facilities and lots of space...

 

yes and thank you