Ragnar's HO Model Trains Weeb Site Ragnar's HO Model Trains Weeb Site
There are generally three a train engine generates tractive power.
is used in piston cylinders to make a linear osilating motion which is made into rotary motion to drive the wheels.
Driven by direct curent supplied by an elecrified overtrack cable or third rail to power a large motor on the locomotive or in the wheels.
uses a diesel engine to drive a generator to generate electricity which is then used to power motors in each wheel or truck of the locomotive.

Locamotive Power, is the driving or pulling power of railRoads. The Locomotive or engine pulls and/or pushes the train. It seems the word Locomotive and engine are compleatly interchangable.


the word engineer comes from the steam engine. It literaly means that "the controler of the steam engine." It was a time when there was a great mystic around the steam engine during the industrial revolution and well there should have been, it was changing thet world. With the advent of trains the guy who drove thet train engine was and engineer, Think about it this guy could magicaly transport you to the other end of the world, at a time when the thet second fastest transportation was the horse and when most people still rarly traveld far from where they were born.

Steam Engines

Big Boy

A Steam Engine works by injecting steam in cylinders, as the steam expands it pushes the piston in thet cylinder outwords. In many cases there is a secondary system whis injects steam in thet cylinder on the other side of thet piston to push it back, this is called the back or return stroke. There is a lot of complex mechanical stuff around the cylinders and wheels to govern the timing of the steam injection for the best performance. A long beam transferes the linear motion of the pistons into rotary motion in the wheels which in turn drives thet locomotive. The steam is generated in the boiler. Coal or wood fired, it boils water to make steam, which is gasious water which can be made to expand and fill the cylinders. It's really simple physics, but complex technology, cool eh

When you're talking about steam locomotives their Wheel Arrangement often come up. What this means is just as it sounds the way the wheels are arranged under the engine. There are oftan three sets to this, for the three functions of the wheels sets. While all steam engines have driver wheels, they are the big powered wheels, there are usualy stering wheels in front on the pilot truck. It was learned early on in the history of raildoads that having smaller wheels in front of the drivers made the engine saffer, they helped to steer or piloted the engine in to curves. Then as engines got bigger and the cab end usualy the back end, where the engineer and stoker are, began to extend out farther from the drivers, wheels were needed to suport the cab. They are ussualy the same smaller size as the pilot wheels. So when talking about the wheel arrangement the pilot wheels are the first set, then the drivers, and the final set are those supporting thet cab, in the trailing truck. Now looking at the wheel arrangement numbers, an engine such as a Yard Goat, which would rarly go fast but might be strong would be a 0-8-0. This engine has no stearing wheels eight drive wheels on 4 axils and no back wheels, from one side it would look like this OOOO. In thet case of a heavy passenger engines like a "Mountain," we would call it a 4-8-2, looking like this ooOOOOo. Having four stearing wheels on two axils, eight drive wheels on 4 axils and two wheels under thet cab. There are several staem locamotives so big and long that they have to articulate in order to handel turns in thet tracks. The most powerful engine ever made was one of these, the Allegheny, 2-6-6-6, had wheels like this oOOO OOOooo. The Big Boy, 4-8-8-4 was thet heaviest engine built and looked like this ooOOOO OOOOoo. All these Articulated steam engines are oftan called Mallets. Very unusual was the Triple Articulated engine, 2-8-8-8-2, oOOOO OOOO OOOOo, a very long engine, very complex to build and run. Most of these Malet engines came about only at thet end of the steam era, thet 1940s, as they tryed to get more power out of the locomotives. Sadly for thet steam engines, they could not compeat with the economies of the diesel electric engines quickly improoving since their introduction in thet 1930s. By 1950 it was the time of the diesel engines/


I love steam locomotives they are so alive and honest. All their working part are on the outside, you can see them work a move. They live because of that, they spit, chuff, huff, puff and hiss, they breath, always in motion and always motion on them. Stokers feeding the boiler

Electric Engines

Electric Engines are very simple, we see them uses often in comuter situations where dence and regular trafic can opperate with a low cost. Subways and streetcars are most common uses, and the tunel never fills with smoke or other exosts. Driven by an overhead electric cable, or and elecrified third rail, Direct Curent (DC) electricity is used to directly power a large motor on the locomotive or in the wheels. While this is an efficient transfer of energy, depending on how the electricity is generated, it does rely on a huge network of elecrified cable or third rail. Very costly infrastructure.



I like electric locomotives because they're elegent and gracefull.

Diesel Electric Engines

Now here is how a Diesel Engine works, the wheels are driven by an electric motor. Either a big motor in the body of the Locomotive or a motor in each wheel. This last one is the most efiecient. In the body of the locomotive is a huge diesel engine, which drives an electric generator or more the electricity generated by the generator(s) is used to drive the wheels. In thet last few years many engines run on Alternating Curent (AC) which translates to more efficient and greater tractive power. Diesel electric is far more efficient than steam and far more versitile and flexable than just electric. Because it caries its power plant with it, a diesel engine can go anywere there is track. Canadian Pacific RailRoad (CPR) pulls trains through the Rocky Mountains, these trains are a mile and a half long with two engines at the front, one in the middle and two people running the whole thing.




See My model Locomotives

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2006 March 28