What is the difference between an engine truck and a pony truck on a steam locomotive? Or are they the same?
A pony truck is a two wheel assembly found in front of the driving wheels, like a 2-8-0 with a two-wheel pony truck and eight driving wheels.
I don’t recall seeing the term “engine truck” in general use anywhere so not sure what it refers to, a quick internet search didn’t come up with anything.
The wheels behind the drivers are generally called a trailing truck. A 4-8-4 Northern would have a four-wheel lead truck, eight driving wheels, and a four-wheel trailing truck (supporting the firebox).
They are the same.
Offhand, I’m agreeing that “pony truck” implies two wheels while “engine truck” doesn’t. I’ll see if the books say anything.
I’ve never seen any reference that implies that a “pony truck” has only two wheels. All that I remember seeing have given me the impression the user has the choice as to which term to use.
Johnny
The Loco Cyc (1941/1947/1950-52) says a pony truck has two wheels. Also the Kalmbach MR Cyc.
It seems an “engine truck” is actually just a truck under the engine-- i.e. the trailing truck is an “engine truck”, altho the latter is usually understood to mean a truck ahead of the drivers.
I’ve never heard of the term “engine truck” but common sense suggests that both leading and trailing trucks could be referred to as engine trucks. Like Johnny, I’ve always thought that pony and leading trucks were synonomous whether they had two or more wheels.
It’s just a guess on my part, but I imagine the term pony truck dates back to the early days of steam locomotion. When leading wheels began to appear on locomotives they were probably given the name pony trucks ala the critters that were out front of the earlier horse drawn cars that the engines replaced.
Mark
Pony Truck? Engine Truck?
I always refered to the the leading truck on a steam locomotive as the “Pilot Truck”. In fact, the “cowcatcher” is most often refered to as the “Pilot”. The “Pilot Truck” does just that, it guides the weight of the locomotive into the curved tracks. Slow (switcher) locomotives seldom have one, medium speed locomotives usually have a 2 wheel Pilot Truck, high speed locomotive most often have a 4 wheel Pilot Trucks.
I believe that on an articulated engine the engine that is free to turn is the engine truck. It is a complete engine ( cylinders, rods, wheels) and it is a truck in that it is free to turn from the locomotive centerline.
From the Locomotive Cyclopedia of American practice By American Railway Master Mechanics’ Association, American Railway Association. Mechanical Division, Association of American Railroads. Mechanical Division it appears that either of the trucks is an “engine truck,” with a two wheel truck being a “pony truck”. The truck behind the drivers is generally referred to as the trailing truck.
Thank you, Larry! I went to bed last night wracking my brain trying to remember how I learned it as a kid.
The way it was taught to me was the truck (2 or 4 wheels) ahead of the drivers was the “pilot truck” and the wheels behind the drivers where the “trailing truck”.
I wonder if the term “engine truck” came about after some engines were built with trailing trucks with Boosters. Steam powered drives for one of the axles on a 4 wheel trailing truck that only worked from about 0 to 10-15 MPH. The CPR had them on their Selkirk 2-10-4’s.
AgentKid