Things that seemed a good idea at the time, but in practice are pretty useless.

The argument doesn't stack up, the Webbs and Drummonds also had independent drive to each axle.

 

Funny how Dugald Drummond keeps cropping up in this particular thread.

 

Network Rail?

 

He crops up on quite a few really. Like Webb and William Dean his locos were either very good or very bad.

 

Based on comments on another thread....Pacers!!

 

Try again

 

AFAIK it worked tolerably well & even did some revenue earning runs

 

They've given 30 odd years of service so like them or not, they're not useless

 

Brakes on bogie wheels?

 

It did, although it was never 'handed over' to the running dept wallahs .... and only ever for freight (in commercial operation).

The rationale for it's construction was solid enough at the time. Ireland isn't blessed with anything like the coal reserves of the UK, with the only significant deposits south of the border being around Arigna - which was the reason the Cavan & Leitrim NG line survived as long as it did, only closing when the entire output was diverted to a new power station. Arigna coal has a very high ash content, making it less than ideal for steam locos.

With oil, then as now, priced in $US, utilising the only readily available 'native' fuel source (other than timber) to protect the scarce foreign currency reserves of that time and with the WWII coal shortages (which actually lasted, spasmodically, until late 1947), still fresh in both the CIÉ's and the Irish Government's memory, it made far more sense than it may seem from a modern perspective.

 

Wardale is very explicit about the reason for feedwater heating in his writings. It is not, as I suspect they were often sold and judged, about saving water and fuel at moderate power outputs; the reason he cited was increasing the evaporation before the grate limit is reached (at which point economy drops off a cliff as a significant portion of the fire disappears up the chimney) and thus allowing higher power output. That's why they were popular in the US, home of sustained maximum power operation, and with French compounds creating 3000+hp at the drawbar from 40 sq ft of grate.

One of the few sustained applications on a large class in this country appears to have been the fitting of ACFI feedwater heaters to the B12/1 class under the LNER, on which they generally lasted until rebuilding into B12/3s. With their relatively small grates for quite heavy duties before being replaced by B17s, they were arguably the most ideal application on the LNER, far more so than 2001. It's noted that the fuel savings were outweighed by the maintenance costs of the equipment, but that probably misses the point of what the equipment allowed.

 

... whereas modern railways are just stationary engines using electrons instead or rope!

Tom

 

True, but it was a rope that could traverse curves readily. Switches on the other hand... But I wouldn't fancy keeping a seal of that length airtight economically even with today's materials.

 

Don't say it too loudly, Didcot will be wanting to build 3 new locos for the line...

James

 

I'd nominate the Holcroft - Anderson recompression loco. Sound thermodynamics but bedevilled by the complexity of all the other equipment needed to get it to work, a tale not dissimilar to attempts to get steam turbine locos to work in practice, in particular the need to provide a forced draft in the aggressive atmosphere of the smokebox.

Tom

 

The only turbine loco which did seem to work satisfactorily was the Turbo motive, LMS 6202, but it wasn't enough of an improvement over a conventional loco to be worth pursuing

 

The underlying show-stopper is that the maximum power which a tube between the track could generate is the cross sectional area of the piston within the tube times air pressure, assuming you could pump to a complete vacuum. You cannot have multiple pistons on a single train. I'm not sure what the inside diameter of Brunel's atmospheric railway was. Assuming it's 15 inches the cross sectional area is (15/2)^2*pi and atmospheric pressure is 14.7psi. That gives you a maximum tractive effort of around 2,600 pounds. Even in the mid 19th century steam locos were capable of much more than that.

 

How about the Fell diesel mechanical? Or the Clayton class 17s? Or the Metro Vick Co Bos?

 

I think it was a 25" pipe which equates to a theoretical maximum of 7,200lb, which would be comparable to the locos available in the 1840s but the weight of the locomotive was removed from the train.

 

There is/was a piece of this pipe at Didcot, but smaller than 25" diameter from memory.