Re: Steam locomotive horsepower...

The Welsh Highland late in Summer held a hill climbing contest on their five miles of 2.5% grade above Beddgelert, with results calculated as drawbar horsepower per square foot of grate area.

Very full results are on the web and I'm sorry that I'm not able right now to give URLs but they are easily Googled.

In a nutshell, the NGG16 Garratts were on a par with the double Fairlies but both were beaten by the Penrhyn Ladies, coupled together to make them equivalent to an articulated locomotive.

The Penrhyn Ladies were built in the 1890s but have been regularly rebuilt since they rescued the Ffestiniog Railway round about 1955. They now have piston valves, 'streamlined' steam passages, really good lubrication systems (which most people neglect to consider) and a fairly high degree of superheat so, although of nicely Victorian appearance, they are perhaps some of the most highly developed steam engines in the world.

Bob Gartside