The one in the front with the pistons on the other side, when compared with the others, is probably a YAHS and the others are SHAY locomotives. Don't laugh. That is the name. They were designed to negotiate left and right 'threaded' curves on mountain railways.
Ah! In truth, I believe the one in the front is a Heisler which has a nearly vertical cylinder on each side forming a V with the driveshaft down the center. I know years back, Cass had one. You can see one cylinder and valve chest at about the mid-point.
Nice shot -- good to see that many engines lined up and steaming.
Indeed, the one in front is a Heisler and the two engines on the back are Shays. I photographed a preserved Shay at Iroquois Falls in Northern Ontario. Contrary to what I expected, the engine is in top shape, but not as nice as this trio since they are live steamers.
These engines were built for hauling logs at low speed on light rails, tight curves and heavy grades (4%) To give you an idea, 2% are considered heavy mainline grade.
Timeless photo and great shot! I wish I was there!
In fact, if memory serves correctly, the Cass line approaches 12% at one point, claimed to be the steepest operating non-cog rail in the country (world?). On the ride down, crewmen operate the handbrakes on the converted log cars used to seat tourists. A trip on this line is must if you're ever in the area.