I usually try to refrain from posting twice in a row, and I really don’t want to seem inflammatory here, but while the technical discussion above is very good, when it comes to the concept of “REALISTIC” effects for steam locomotives, I have to take issue with some of the items on the list of things that DCC does really well to enhance “Realism.” Understand before I go any further, that the discussion of why the now infamous Ames Super Socket missed the boat (and not just by ending up on a train) is entirely correct … the issue I’m taking is with the discussion of what a steam locomotive must do to be “realistic.”
To begin with, starting a steam locomotive up is a long process. It starts, generally, with a couple of guys balling up newspaper and throwing it into the firebox, and after a couple of weeks worth of papers balled up sheet by sheet, and a couple of Sunday editions thrown in (literally) for good measure, some scrap lumber, a coffee canful of kerosene, and whatever else that’s lying around, unwanted, and appears to be readily flammable get thrown into the box. A match is struck (or, for the more seasoned, generally a couple of five minute fusees) and things start happening… sort of. For the next half an hour, the idea is to get a wood fire blazing in there, and to add some coal so that eventually what you end up with is a coal fire. As you start to actually have some coal catch, some shop air can be run through the blower (there’s a connector in the line provided for hooking it up) to increase draft… but if you’re starting at 7AM, you’re not really getting the simmering and cooking sounds until well after lunch, when you’ve finally managed to heat all that water and you’ve got a good blazing coal fire going. Still at this point, standing fifty yards from the locomotive, you’d probably only hear the bang of the firebox doors, and some conversation at this point. When steam does begin to come up, it takes a couple of hours to build to anything approaching operating pressure… and even getting enough that it makes sense to disconnect the shop air, and run the blower on steam is an accomplishment. It’s not really until you’re at or near working pressure that things really start happening, and it’s ok to open up the valve to the turbo, start the pumps, and get going on actually being ready to move that there’s a lot to hear. To condense all that into a 20 second “light off” sound with some fire flicker is like shortening the national anthem to “Oh say can you see the home of the brave?”
And … the turbogenerator I just mentioned. Generally, the turbo is spun up when the engine leaves the pit, and runs until the engine is shut down. There are exceptions to this, certainly, but it’s generally how it works. There’s a switch in the cab that is pushed forward one click for dim, then another for full bright headlight forward… or one click back for dim and another for full bright on the rear lights. In later days, there was an option provided for both lights to be on for switching purposes… but it was a later addition. Only on some restored locomotives (and generally, the smallest of these) was the headlight wired directly to the turbo, so that when it spun up, it’d come on dim, and slowly come up to full brightness. If anything, the turbo sound should slow down when the headlight is turned on, as the generator loads up when power is used. The same is true of shutting it down … only when you have a museum that has restored a locomotive, and only runs the headlight on the front at night or something is there no switch, and the fade up/fade down happens with turning the turbo on and off.
That brings me to the noise of the “Johnson Bar.” Technically speaking, the Johnson Bar is the name of the manually operated very long vertical lever on the engineman’s side of the cab that works the reverse gear … manually. That’s how it’s found on most narrow gauge, and smaller standard gauge locomotives. ALCo in particular and others thereafter began to market “power reverse” units in the more modern era of steam locomotives (see air brake and electric headlight days) that were air operated… the lever was in the same position, and had a rack and quadrant like it’s older cousin, but was generally a much shorter affair, and worked a small valve ahead of the cab on the engineman’s side. This valve operated a cylinder, very like a brake cylinder, under the running board (in many cases) which was connected to the reverse gear in the same manner the older manual one had been. A secondary connection connected the piston to the reverse lever itself. In this way, pushing forward on the reverse lever would cause the reverse gear to transit forward (and down) and to move the lever along with it, allowing the engineman a sense of where the gear was for cutoff purposes, stopping the pressure would cause the mechanism to “catch up” and stop moving wherever the lever was left. To center up, or reverse, pressure was applied in a backwards direction with the same type of result. This meant that moving from center to full forward or reverse or back again would cause a “whooshing” sound as the piston travelled (and exhausted air from the opposite side) moving the gear. A manual Johnson Bar can really only be heard if the rest of everything is very silent, and then it’s really just a clank as it hits the stop. So, to be “realistic” if you have a locomotive new and large enough for power reverse, then you might “hear” the johnson bar. Phoenix has a “Johnson Bar Effect” which is related to the FUNCTION of a johnson bar on a steam locomotive, that is, when moving at higher speeds, generally an engineman will “choke up” on the reverse gear, moving it closer to dead center. This means that more of the piston’s travel is powered by the expansion of the steam, and not by directly admitting steam to the cylinder … and therefore less steam per stroke is used. A heavy throttle setting with the gear thus “choked up” tends to produce a very staccato chuffing sound in the stack, and is popular with digital sound users on model trains, as it means that the “chuffs” are more individually distinguishable at higher speeds… whereas at lower speeds, “chuff chuff” can become “whuuuf whuuuuf” as with starting a heavy train and requiring less cutoff and more steam.
So demanding to hear the “johnson bar” may not be realistic depending on your prototype, and may not be the sound folks think it is.
Which brings us to lighting effects. On a real steam locomotive, assuming one powered by coal, you don’t generally see fire in the ash pan unless the locomotive is being steamed up and the bank is being broken out and raked, someone has done an occasionally necessary shaking of the grates, or something bad has happened. The fire is in the firebox, where it can heat the water. When the firebox doors are opened, the cab will light up brilliantly orange at night, requiring a good fireman to “one eye fire” so as not to ruin night vision. (Good for enginemen too… ) Flickering fire below the ash pan is generally not seen, although, at night you may see a warm glow, and occasionally some sparks from the grates being shaken or something falling through. Oil fired locomotives occasionally will flash back and out the bottom, particularly with massive changes in draft, as with wheel slip, etc. but the principle is the same; the fire belongs in the firebox. (and, since oilburners don’t need or have grates, the flashback is through opened dampers front and rear, and sometimes hard to see, depending on the construction of the locomotive. It’s a lot like watching your furnace at home. So… if you’re going to simulate a fire, the best effect I’ve seen is the Sierra, which brightens up when the "fireman’ is shovelling… and the doors would be open… and dims down when not; assuming the fireman left the doors on the first notch to keep things from getting too hot, you might actually see this. Marker lights are generally on, or off. The kerosene ones were lit when hung up, and the electric ones plugged in and generally left on, when on a train that required them.
I am not for a moment condemning realism in model trains. I particularly like the advances in digital sound that make the locomotive come to life. But I think it’s possible, in the name of putting something new on a model, to come up with things the model does that the prototype wouldn’t have … or to someday have someone watch a locomotive after learning on the model, and wondering why it wasn’t as realistic as the model was! After all, the headlight came on as if turned on by a switch, I didn’t hear a thing when the reverse gear was moved forward, the marker lights weren’t on at all (daytime!) and the fire looked bright white when the fellow opened the doors as the train left, not orange and red like it’s supposed to! And, while he dimmed his headlight when approaching the station, I couldn’t help but notice he didn’t turn both headlights on while making the runaround move in the yard. It’s just not like the model!
Here’s to realistic realism.
Matthew (OV)