Maybe this shoud go in the Locomotives forum but here it goes… I was wondering what would be faster (without a load): a 2 cylinder or 3 cylinder shay (asuming they are both two-truck class B shays).
Speed would be determined by the gear ratio and ultimately would be limited to how fast the pistons could move, not the number of pistons.
Maybe 3 cylinders could move the pistons a bit faster due to the extra power available, but, as the speed goes up, the power required to go faster would be exponentially greater, so at some point a small amount of additional power would not be enough to appreciably move the pistons faster.
There are other things that might be limiters of top speed… firbox size, boiler capacity, pipe sizes, etc. (can you feed 3 cylinders enough steam to keep them moving at top speed?)
Personally, I think if the gear ratios were the same, and same sized wheels, there would not be a lot of difference between 2 or 3 cylinders as far as top no-load speed goes.
I would expect that the three cylinder might ba a bit quicker in acceleration, but with the same gearing and wheel diameters, the Top Speed should be the same. Shays were built for torque rather than speed, this is kind of like asking which is faster, a Tortise or a turtle, the answer is NEITHER is FAST.
The Shays were built for low speed lugging, on tracks that were often rough, had steep grades and sharp curves, where speed was not expected. IIRC, the top speed was in the range of about 15 MPH. Still not consider FAST, but for a geared steam locomotive, the Heisler tended to be a bit quicker. The “V” motor and centered boiler and machinery would definitely have helped in that regard.
The Shay are the best known, but the Shay, Heisler, and Climax were all sucessful and interesting locomotives,
Doug
Ya, I knew they were both pretty slow-I was just wondering if either was faster. Thanks for your replies.
1925 of The GCRR. Could do at least 17 miles an hour at NCTM. She is got to have boiler work due to the wrong chemicals were put in the boiler. the chemicals came from the water softing company.
You will have a tough time comparing two-cylinder and three-cylinder class B Shays. Two-cylinder two truck Shays are class A by definition. Three-cylinder, two truck Shays are class B by definition.
There was in the very early days at Lima a two-cylinder three truck Shay constructed, that did not fit the later catalog descriptions. Maybe we should refer to this odd-ball locomotive as a class A+Shay!
Top speed in either case would most likely be determined by when engine parts begin to come unglued and fly into the underbrush.