Longest Tank Engine Runs

On the brighton 4-6-4s with well tanks Holcroft also records "the running department [said] it was difficult to do repair work on the well tank if serious leakage occurred and it might be necessary to lift the boiler ... in order to get access to it"

 

Torwards the end of their life some of the Hughes 4-6-0s were fitted with narrow rings on the valves instead of the wide Schmidt type rings. This reduced their coal consumption but they were scrapped shortly afterwards (E S Cox, Locomotive Panorama, volume 2)

 

So it would seem that Billinton had solved the 4-6-4 stability problem but acquired a maintenance problem. Nicely illustrates that design choices tend to have both upsides and downsides, both benefits and costs.

 

We seem to be getting a bit off topic, but Jimc ought to also quote also from Vol 2 of Holcroft's 'Locomotive Adventure' on the Brighton Baltics. Steam Index is also a good source.

The Brighton Baltics and the N15X when converted to tender locos were always hampered by small diameter piston valves of relatively short travel so that they were 'constipated' and the advantages of economical expansive working at short cut offs were lost. They weren't happy at shorter than 30% cut off.

Going back to the Greenly 'Halton Tank' in 5"g, this is a very old poor design, and requires considerable work to get a decent example in miniature.

Cheers,

Julian

 

For a bit of a laugh. A report of a run from Liverpool Street to Brighton with a Terrier in 1880.

http://www.semgonline.com/RlyMag/MemRunBrightonTerrier.pdf

 

Dunno if it counts, but in 1906, IWCR 'Railmotor No.1' apparently made the delivery journey .... over a few days .... from Scotland to (IIRC) Southampton under it's own power, purportedly to give the relevant folks a first hand view of one of these beasties in the flesh. That must've been great fun for the crew!

 

Does it have to be UK? In the mid-30s, PKP built a class of 25 2-10-2T tanks (OKz32) to haul the Krakow-Zakopane services, a 90 mile line which is steeply graded and involved three reversals, hence the design of a loco with a symmetrical wheel arrangement.

 

The "other" Fowler tanks - ie the Irish Class WTs regularly ran Belfast - Londonderry (90 miles), to Portrush (65 miles); after 1958 to Dundalk on the Dublin semi-fasts (58 miles) and right at the end of steam were regularly used right through from Belfast to Dublin (112.5miles). Not quite the 120 miles of their cousins on the Central Wales line - but a lot faster!
Wonderful locos!

 

I gather that the NCC rather like the 'South of the Thames' lines was going over to 'All Tank Engines' after WW2 as they could cover all the jobs on the system

 

I have always thought this business about "showing those damned foreigners how to run trains" was more xenophobic than authentic, especially in view of the l.b.s.c.r. not being noted for speed at the time. French trains had been limited to 120 k.p.h. (74.5 m.p.h.) since the time of the Third Empire which suggests there were examples of speeds far in excess of 50 m.p.h. being attained. There is no doubt about No. 40 demonstrating the Westinghouse brake and it is not unlikely that speeds of 50 m.p.h. were attained then.

As co-author of a booklet about the 140th. anniversary last year of No. 40's trip to Paris, I tried (and failed) to find any evidence of what seems to be a legend about the boat trains. I did find though, a contemporary account, by Anatole Mallet no less, of the locomotives shown at the Exposition which settled one or two points. No. 40. (now No. W11) is one of the most historically significant machines currently serviceable.

 

I gather that the NCC rather like the 'South of the Thames' lines was going over to 'All Tank Engines' after WW2 as they could cover all the jobs on the system

Yes, that was the view of Major Pope when he took over running the LMSNCC after WW2 - hence the order for ten tank versions of the Moguls of 1932. Later, a further eight were ordered, but delivered in UTA days

 

Absolutely, and there's one still going on the mainline (although currently being re-tyred)!
Strictly speaking, not Fowler tanks, since they were post-WW2. But the design was a tank version of the Moguls delivered very early in the Stanier era, and based on the Fowler 2-6-4Ts. I doubt Stanier or indeed Ivatt had much involvement in the design, as the NCC seems to have ordered them themselves.
They were incredibly economical (Nock reports than one of the Moguls was regularly run at 7% and even 5% cut-off!), but nevertheless the WTs were limited by water capacity on their longer duties. The UTA even tried running one with a tender from an NCC 4-4-0... This does not seem to have been a success.

 

Actually, the tender used was a Mogul "Small tender" - that is of the ones which came with the first batch of moguls.

The idea was that they could run to Dublin non-stop - a requirement in summer when the UTA ran tourist trains in association with their coach / rail tours. Also for the rugby trains to Dublin in winter.

With 2,500 gallons in their tanks, the Class WT could make Dublin with a single stop for water.

 

A question for the hive mind

I’ve been re-reading LTC Rolt’s ‘Red for Danger’, there is a short section on accidents involving tank engines on expresses. It highlights a couple in the 1880s in Cornwall and Devon (Doublebois And Tavistock) as well as Charlestown Curve in 1912, Raynes Park in 1933 and Sevenoaks in 1927. Rolt argues that tank engines are more unstable. So my basic question is whether or not these accidents influenced loco design away from using tank engines for longer and express turns.

I am also assuming that the further a tank engine has to go the more coal and water it has to carry and so its weight distribution will be more variable compared to a loco and tender? I am assuming that this is what Rolt means when he says that tank engines are more track sensitive at speed.

 

The centre of gravity of a tank engine tends to be higher than the equivalent tender engine because the water in the tanks is higher than in a tender. When it moves about in the tanks the instability is increased ( I hope I am making sense). many years ago I drove a 5" gauge River class and this seemed to roll more than a similar tender loco.

 

Thanks, that does make sense.

Would a tank engine with full tanks be more stable than a tank engine with 1/2 or 1/4 full tanks? Thinking back to the op and limits on tank engine runs, I would assume that you would be limited not just by how much you can carry but when the loco would become most unstable.

 

Following the Sevenoaks accident, the Southern "River" or "K" class 2-6-4 tanks were rebuilt as "U" class 2-6-0 tender engines. So clearly, yes, loco design was influenced away from tank engines for express work.

The other recorded influence at the time was on the LNER, where a large new passenger tank design had been under preparation. Following the Sevenoaks accident, this project was paused while Gresley reviewed his options. Ten additional Great Eastern type B12 4-6-0s were ordered as an interim solution instead of the tanks. After a couple of years delay, the LNER large tank emerged in 1930 as the Class V1.

I think it is almost certain that earlier accidents and Railway Inspectorate criticism would have influenced railway boards and CMEs to be cautious about using tank engines on fast trains. But I can't quote any specific examples.

 

The other Southern example was the Billinton (LBSCR) 4-6-4Ts. Shortly after the first two were built, one of them - 327 - derailed at Fishbourne, fortunately without significant consequence. Subsequently, the two locos were temporarily withdrawn and rebuilt with well tanks. The side tanks were blanked off to reduce capacity (though interestingly externally they retained the same size, purely for aesthetic reasons). The three tanks were arranged such that the side tanks drained first; the side tanks had additional baffles fitted; the Weir feed pump and Westinghouse air pump were moved from the tank fronts to between the frames. Some of the framing and the dummy tank sides were replaced with material of thinner section. So clearly stability and centre of gravity were a concern.

(Later in their lives, the locos were rebuilt as 4-6-0s, but that was not because of inherent concerns about stability, but because of Brighton electrification meaning the duties they had been built for disappeared, so they were transferred to the Western section where greater range was required. Interestingly, when the first two were ordered, they were ordered as a 4-6-4T and a 4-6-0 tender engine, the tender for which was constructed, but which loco ended up being converted to a 4-6-4T while still in the erecting shop).

With regard the K class tanks on the SR, in the wake of the Sevenoaks disaster, high speed trials on the East Coast Main Line were carried out without significant stability issues. There are details of the trials contained as an appendix within the accident report; interestingly King Arthur class No. 782 was also tested and, if anything, seems to have ridden worse than the tank engines on the SR track. See https://www.railwaysarchive.co.uk/documents/MoT_Sevenoaks1927.pdf

It seems the K class locos were track-sensitive, rather than inherently unstable; i.e. it was the combination of the characteristics of the loco and track together that caused the problems. Nonetheless, since wholesale track relaying clearly would take years to achieve, reconstruction as 2-6-0 tender engines was clearly the only viable course open to the SR.

Tom

 

Stability at high speed is an issue with all steam locomotives, I understand that Gresley had inclining trials done on the (old) A1/A4's so that the Centre of Gravity should be ientified and calculations made about their safety at speed.

In Tank locomotives there is the additional issue of the 'free surface' effect of water in the tanks. Any Merchant Navy officers may be able to expand on this

 

Simple answer - yes. When a tank is slack - ie less than full - then there's a phenomenon known as 'free surface effect', where the water moves in the tank as the locomotive sways during running, and thus the centre of gravity of the water moves. The bigger the surface area at the top of the water, the worse it gets. Internal baffles will help reduce the effect, but some designs (such as the River class) are worse than others.

Free surface effect on a larger scale was, of course, what capsized Herald of Free Enterprise off Zeebrugge, Normandie in New York, and an Empress liner in Liverpool, amongst other ship disasters.All due to large amounts of water moving about - the former when the cargo deck flooded, the latter two when water was being used to fight fires, with it not being pumped overboard quickly enough.