Re: USA 250-256

> If my memory is correct, she has 19" bore
> cylinders and was
> rated for at or about the same tonnage as the
> smaller versions with
> 17" cylinders. All that potential power going
> to waste.

That is correct Tom, the cylinders are 19" X 20" and the drivers are 44". The Baldwin Mikados were 17" X 22" with 42" drivers. Also the boiler pressure for the Baldwins was 185# vs 170# for the Alcos, presumably to improve the factor of adhesion. We reduced the boiler pressure on 19 to 150# to aleviate wheel slipping. I have never seen a satisfactory explination as to why the SV went with this configuration as the Baldwins had already proven themselves on the line. The Alcos might have been made heavier but in 1920 the SV still had 45# rail.

On good track the Alcos could reach 50+ MPH, which might have been a selling point except that the SV had only two relatively short stretches where this was possible. The locomotives could have been superheated, but the SV was very conservative and probibly thought that, burning wood, the effort would have been wasted.

At any rate, and for whatever reason, they did produce two very good looking locomotives.