Chattanooga Modular Modelers

Teaching and Inspiring through the art of Model Railroading

Chartered in 2013, CMM, Inc. uses the hobby of model railroading to educate the public about the role the railroads have played in our nations history, techniques for construction of portable displays, electric and electronics principles used in modern devices and control circuits and more...

Background colorization images courtesy of Tom Alderman, Marietta, Ga. 

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Steam vs. Diesel: as far as I’m concerned, steam locomotives will always be king, holding more of a fascination for people than diesel locomotives ever could. If that is true, then where are the steam locomotives? I understand why, at least partially, why steam was defeated by diesel, but I will always mourn the passing of steamers. One comforting thing to know is the most popular locomotive horn is the five chime model K5LA steamer air horn used on many of the most modern diesels now. I will, in this article try to explain what I understand caused the demise of steam. The bystanders are the group that greatly admired the steam locomotive, but they were not the operators, both directly & financially. It seems the C.E.O.s, managers & investors are slaves to the bottom line: rightly so, take your pick, Red or Black. They always seem to greatly favor Black. Every steamer seemed to have a life & personality all its own. Sounds & sights of steam locomotives were profound & captivating. Diesels make a boring, pathetic hum. When a steamer went by; there was a visible motion of power in side rods & valve linkage, with drive wheels taller than a man. Steam & air hissed at every orifice. Fire could usually be seen under the cab, heat seemed to be everywhere.
    Your automobile engines’ nomenclature is: a naturally aspirated, or turbocharged or supercharged, four-cycle internal (inside the cylinders) combustion engine. The four-cycles are: intake, compression, (spark ignition is not a stroke) power & exhaust. This means only one out of four strokes was powered. The steam locomotive is a one-cycle external combustion engine, the fire is at the rear of the boiler, not in the cylinders, only steam is allowed in the cylinders. This means every stroke of the pistons & drive rods was a power stroke. It literally took a two-man crew to operate a steam locomotive. The steam locomotive was a dirty place to work. It was either too hot, or too cold, or too wet, almost never just right, & always too noisy. The engineer controls the speed of the locomotive by moving throttle & reversing lever, A.K.A. Johnson bar, as well as the brake & sand system. He can reverse the locomotive but he cannot steer it, the rails do that little chore. The fireman controls the water & fire levels inside the boiler. He sets & maintains the water levels in the boiler by using water pumps of varying types while watching sight glasses that indicate where the water level is. Oil injectors or coal stokers spread the fuel across the grates for an even-burning hot fire that was used to boil the water into steam. When water is heated to become steam it expands over 1600 times, making steam power possible.
    If more power was needed, extra locomotives could be coupled on. There was a problem with extra locomotives: expense of an extra crew, two men for each locomotive. Expenses did not stop with crews. The reciprocating parts of a steam engine were difficult to balance resulting in an extremely heavy consistent pounding of the track structure including rails, cross ties, spikes, tie plates, ballast, bridges & turnouts as well as locomotive frames. Expenses did not stop with track structure. Train brake shoes, made of cast iron, eight to sixteen per car, had to be replaced regularly because that was the only way train speed could be controlled on long down hill stretches. Wheels required machining or replacing because the brake shoes could cut grooves in the wheel tread or would get wheels so hot they would crack or, if on an empty or light car, slide its wheels putting flat spots on the wheel tread & increasing rail wear. These flat spots would hammer the track structure like an out-of-balance wheel, or hammer the wheel itself, causing different types of wheel damage & failure. Flat-spotted wheels could damage wheel bearings, freight car frames, draft gear and lading by their incessant hammering. Did you ever notice that even brand new cars & locos had rusty wheels & couplers? Why do you ask? Because cracks can not be seen if covered by paint. Expenses did not stop with freight & passenger cars wheels & brakes. The locomotives required large amounts of labor to do even the simplest maintenance. Every time a steamer completed its run it had to go to the round house or maintenance area, for refueling of many tons of coal or hundreds of gallons of oil & thousands of gallons of water & hundreds of pounds of properly dried sand. Greasing & refilling of lubrication oil reservoirs were performed. Sometimes they were washed, especially if they were passenger power or new freight locomotives. The boiler had to be regularly washed out to eliminate scale & other water deposits. If it was a coal burner, ash had to be regularly dumped & the residue cleaned out. Maintaining adequate supplies of good, clean, properly treated water, was a major problem, especially in desert areas & where freezing temperatures also abounded. A big steamer could nearly empty all the water out of its tender in a short time, as little as forty five minutes on some stretches. The tender needed a water refill two to four times more often than refilling coal or oil supplies. Two notable exceptions to coping with refilling water supplies were the Norfolk and Western Railway & the New York Central. The N & W coped by using a canteen car which was a steam engine tender that had all its volume converted to carry water coupled immediately behind the regular tender. The N.Y.C. coped by putting long pans of water on the cross ties between the rails & scooping the water up at track speed into its’ tenders with a powered scoop lowered & raised at the right times. After all the maintenance was performed, steamers had to be turned around on either a turn table, or a Y, or a reversing loop before they could return to home rails because it was considered necessary that it be run forward only. Actually, the steam engine doesn’t care which direction it was run in. All the engineer controls were just located to be run forward. Major maintenance had to be performed on a weekly or a monthly basis. Most steamers had to spend at least one day a week in the roundhouse for even routine maintenance. 
    I refer to the diesel as a fancy painted, powered boxcar. Another person referred to the diesel as a brick on a flat car, (I wish I had thought of that.) The diesel is a two or four-cycle internal combustion compression ignition engine, either naturally aspirated, or turbo charged or super charged.  The Union Pacific Rail Road discovered that at that time; five diesels were required to replace one Big Boy 4-8-8-4 steamer. If more power was needed, which is normal however, since diesels aren’t all that stout, merely coupling two, three, four, five, six, seven, or eight locomotives together by plugging in extension cords, called M.U. (multiple unit) cables so one engineer can control them all as one unit. M.U. diesel power is very economical because one crew controls all the available power. The only regular servicing a diesel requires is refilling the diesel fuel tank & top off the sandbox, sometimes washing the windshield. Air filter element replacement was a constant maintenance problem until the centrifugal air filter came into common usage. Once a month the oil filter & the oil in the oil filter, 25 gallons approximately, would be changed with an oil sample being taken for analysis by the railroad lab. The oil sample would be analyzed, looking for excesses of different metals, coolant, water, or dirt. By analyzing oil samples periodically problems could be detected before they became serious enough to cause expensive damage. Then the locomotive would be called in and taken out of service for a minor repair before it became major.    The entire volume of crank case oil, about 250 gallons, was changed once a year.
     Diesels put very little more wear & tear on track structures than freight cars do. Diesels can now control train speed going down hills without even touching the train brakes since dynamic braking has come into common usage. Dynamic braking is like pulling in reverse, kinda-sorta. Diesels pull their trains by having the diesel engine turn a 600 volt generator or, in newer versions, an alternator, which puts out electrical energy that goes through the locomotive control system to electric motors, called traction motors, one on each axle. A locomotive with eight wheels has four axles, four traction motors. Each motor turns two wheels. Some locomotives with twelve wheels have six motors.  There are some locomotives that have sixteen wheels, eight traction motors, all wheels powered. Some of the twelve wheelers only have four traction motors, mainly to spread locomotive weight, like on lightly laid branch line rails or for greater stability at high speeds like the Alco PA-1. When braking is required to slow the train down to about five or ten miles per hour, the engineer engages the dynamic braking system, which he can vary from maximum to minimum. Dynamic braking operates by causing each motor to become a generator. When a motor is forced to generate current its’ resistance to being rotated greatly increases, so motion, kinetic energy, is converted into mechanical energy & mechanical energy is changed into electrical energy with some loss making heat. The electrical energy is carried to the roof of the  locomotive where it heats a grid of iron bars; like a bionic toaster on steroids, with some power being siphoned off to run an electric fan, so electrical energy is changed into thermal energy. The fan pulls a large volume of air across the hot iron bars raising the temperature of the air & keeping the temperature of the iron bars below their melting point. So the motion of the train is kept within safe limits by heating the surrounding air. A full stop must be done by the trains’ air brakes. Sir Isaac Newton is satisfied. We didn’t break his Law Of The Conservation Of Energy. Our train wheels were kept cool. Our brake shoes didn’t have a lot of wear & tear put on them so our maintenance team can breathe easier too, so what are you complaining about? Everyone is happy but the steam lovers. 
    Most of you know that any energy cannot just be discarded because we wish it to go away. Case in point: Train is going down its’ track, school bus gets on track & stalls. Bus is full of small children that are too scared to get off the bus. Engineer really, really wants to stop his train, & not hit bus. Train hits bus anyhow. Why? Because the physical law of Kinetic Energy of a Mass in Motion cannot be eliminated until all its’ energy is converted or dissipated into another form of energy. 
A locomotive is like the blacksmiths’ hammer. It has lasted over fifty years; since we’ve only had to replace three handles & four heads. Several years have passed & the only original thing showing on either diesel or steamer is the identification plate.  When we remember the chug chugging of steam exhaust, so powerful that it reverberates in our chests; recalling the haunting wail of a lonesome steam whistle echoing through the hills  on a dark, cold night, & the hollow clank of side rods as a locomotive drifts by, we are reminded that although steamers may be gone from the scene of commerce in action forever, as long as the steam lovers still exist, steam will still always be considered king. 
       Written by Bob Swanner 4/20/02 Rev.7/11/13