What might have been Part 2: 4-8-2 mountain type

[bikkuri bahn]

The 78-2 type (1923) was a design for a 3 cylinder 4-8-2.  It utilized the D50 2-8-2 boiler but with a 3 cylinder configuration (apparently there was a 2 cylinder design also, the 78-1, of which there are no detailed records).  The cylinders had a bore x stroke of 450mm x 660mm, the same dimensions as the C52 pacific type.  Drivers were 1600mm (5ft 3 in), compared to 1400mm on the D50.  Top operating speed was 90km/h, with cylinder tractive effort of 13.85 tons, or about 30,500 pounds.  Axle load was 15 tons, giving reasonable route availability. The intention was to haul heavy express sleeper trains.  However, the length of the locomotive was 18.8m leading bogie to last tender wheel, which was .5m longer than the standard length of turntables, which was 60ft, or 18.3m  This, coupled with uncertainty over the three cylinder configuration, led to this design being shelved.  Trials with the three cylinder design in passenger locomotives continued with the C52 type, which, being a pacific design, was shorter in length.

 

*All data and picture from the book maboroshi no kokutetsu sharyo JTB Publishing 2007.

78-2.bmp

[marknewton]

That looks rather handsome, BB. Can we have a bigger picture please? 

 

Cheers,

 

Mark.

[bikkuri bahn]

Sorry, that's all I got.  If you want to, get a nice picture of a D50, and imagine bigger wheels and a four wheel leading truck, and there you basically have a 78-2.  It shares the same low slung look and capped stack as the D50 or D60, which is a good thing.