Condensing Locomotives

[darwins]

I am trying to find out a little more about steam locomotives fitted with condensing equipment for working over the underground lines in London or Glasgow. (Metropolitan / GWR / MR / GNR / Caledonian)

Does anyone know approximately how much of the exhaust steam was returned to the water tanks and condensed?

Presumably the pipes leading to the tanks branched off the base of the blast pipe close to the cylinder exhaust. I am guessing that much of the steam still went up the chimney to produce a draught. Does anyone have more details?

Condensing would result in hot water in the tanks, which could not be delivered by a normal injector. I understand that these locomotives were fitted with steam operated pumps in place of injectors. Was this one pump and one injector? Or was it two pumps? Hot water injectors were later invented. Were hot water injectors rather than pumps fitted to any of these locomotives? Does anyone have any information about the steam pumps used?

 

[Ploughman]

Also the MerseyRailway in Liverpool.

Mersey Railway locomotive No.5 Cecil Raikes

The Mersey Railway opened in 1886 to link Liverpool and Birkenhead by means of a tunnel under the River Mersey. 'Cecil Raikes' (1892) was one of the initial batch of eight locomotives delivered to the Mersey Railway by Beyer Peacock and Co Ltd, of Gorton, Manchester, prior to opening. The severe...

www.liverpoolmuseums.org.uk

Beyer Peacock Works No 2605 Cecil Raikes 0-6-4T Mersey Railway

Power ClassificationIntroduced1885DesignerCompanyMersey RailwayWeight – Locomotive67t 17cwtDriving Wheels4ft 7ins Boiler Pressure150psiCylindersInside – 21in x 26inTractive EffortlbfValv…

preservedbritishsteamlocomotives.com

Mersey Railway - Wikipedia

en.wikipedia.org

 

[ThirteenArches]

You have to supply about 4.2kJ to raise a kilogram of water 1°C. Each kilogram of steam condensed releases about 2250kJ, so can raise about 6kg of water from cold to boiling point. So, assuming you fill up with cold water at 10°C, the Class A 0-4-4T with 4500 litres capacity used, at maximum when condensing, about 83% of its water for cooling, and about 17% for actually running the train (and idling). And all that hot water was thrown away.

Getting rid of the heat is the main reason condensing, the only simple* way to get steam engine efficiency over the limit of about 14%, never became pracical on locomotives, and why the great billowing clouds from power station cooling towers are so impressive.

*You could perhaps run a Stirling "hot air" engine on steam that is held over 100°C throughout the cycle I suppose.