It was recently brought to my attention that the owner of the railroad where I work during the summer months recently took his steam locomotive out to haul freight. The engine is a 1915 Baldwin 2-8-2 light Mikido. Reportedly, as he was traveling down a 2.5% grade, he opened the throttle slightly and pulled the Johnson Bar back into the 'reverse' position to help slow the train down. Has anyone else ever heard of this method? I should think this is not a safe operation or at least very hard on the drive train of the locomotive!
Bill, Very common usage. And yes, if you don't know what you are doing, you can break things. Early form of dynamic brakes.
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Johnson Bar braking: It was not at all uncommon when slowing down, or drifting down grade to "Ride the Head" or "Ride the Steam". The move was never fast. When you topped out and were gathering the cars was when it was a little tricky until you (were supposed to), get used to it. It was to save air, and wear and tear on the train brakes. It was usually when your engine had lots of traction and not too likely to slip the drivers. If you were running a light engine with heavy loading, the Johnson bar was more likely to slip the engine than provide much braking effort. The move was made by gently pulling back on the Johnson bar to almost center, and riding just the steam expansion, (1,700 to one). As the cars would begin to bunch against you, they would be pulling the rear cars up over the hump, so you wanted to just stay with the flow but not gain any speed. As more cars came over, you would grab a notch or two into reverse to introduce a little live steam so it could act like a compressor which applied a sort of braking effort. Up to a point reversing the Johnson bar would hold the engine back, but if all the cars were pushing and you began to feel the engine slide, you then had to give the brakes some pressure to hold what you had, but not enough to slow the cars enough to put slack in the couplers. Then you could ease off the Johnson bar and take the reversing load off your connecting and drive rods, which by then were probably clanking and banging to beat the band. In some of the VCR tapes, I have noticed engines that were "Riding Steam" as they came into a station. It is a sound you can not hear except under these conditions. I have never talked to anyone who road steam all the way down, it was always just to set the train for a grade and set brakes evenly. It was not unusual to "Run Ahead" of your train if the grade was fairly short and no dangerous curves at the bottom. That is when you might top the pass at say 15 mph really pulling under full steam, then let her run up to maybe 40 to 50 as you came out on the bottom. It really depended upon the conditions, like if the bottom was a sag with another climb on the other side. That called for a whole different set of moves. Probably today, with all the computers, it is entirely different.
Thanks Watash ... I was hoping that you would see that poser and give me an example of how it's done. Do you simply just leave the throttle out, or do you have to shut it down somewhat? We noticed that there was a few leaks around the tubes in the firebox afterward and suspect that it was caused by too little of a fire allowing excessive cold air to be drawn in by the unexpected draw caused by leaving the throttle out *?* Anyway, we are restricted to 10 mph(8 miles) and we have lots of steep, curvy rail along the way, both uphill and down. I'd like to try that 'Riding the Steam' next summer sometime. We'll see.
Yes, the throttle is way down, you would have shut the throttle almost off topping out so you don't out run your cars and snap a knuckle! Keep your fire up, plenty of water over the crown sheet, and gently easy back same as you would in a car pulling another car with a chain behind you. When you have topped out the car behind is still hanging on the chain, so you do not want to gain speed as it comes on top. You are going to be pushed by that car going down, so you want to gently slow up just enough to allow the car to catch up, which means you have slowed a little. When the car bumps you, it is going to want to coast, and all you want to do is keep it from making you coast faster along with it. You can apply some air and ride the brakes of the car all the way down, which is going to really heat its brakes up, or you can use your "Jake Brake" ergo "Dynamic Brakes" "Ride Steam" by giving a little reverse, and just enough steam to hold your speed. If you gave the Johnson Bar full reverse, the drivers would spin slowly in reverse, as the train pushed you down hill, so you only want to know if the engine has enough traction alone to hold back the train weight, or do you need train brakes anyway. If you need train brakes to prevent gaining speed, then take the johnson bar down to almost shut off and shut the throttle down to just enough to prevent slipping the drivers. If you leave the throttle wide open, you will pull a cold draft, and perform all kinds of ugly things inside the boiler. Eight miles is a long way, for brakes, but not so far riding steam so long as you don't slip drivers. The danger in slipping drivers, is heating up the driver's tires to where they expand and come off the wheels! They are shrunk on you know. If riding air is going to slip your drivers, then by all means set the train brakes, and let off the steam until your drivers turn OK, not freely, buy not slipping. Don't dump air once you have set train brakes, or you can have a runnaway. (A runnaway is not a fun thing to happen.) Apply a little air. See what it does, a little more if it is still gaining speed. Only apply enough to allow a gentle increase in train speed, so you will bottom out at a safe speed. All this should happen at the top of the grade, not half way down. If riding steam, and full train brakes isn't going to hold her, there is one more thing you can do. Keep your knees straight, face the tender, bend over, grab your ankles, and kiss your butt goodbye!
