Train Handling With Steam

[JamesP]

Kootenay, very interesting reading... I enjoyed it tremendously - not boring or rambling to me!  If you ever get down to the Ozarks, come by and we'll shoot the bull and inhale some steam, cylinder oil and coal smoke (I've got some dirty Illinois coal that is just wonderful)!

 - James

 

[Kootenay Central]

Here are some random thoughts and items of my own personal experience over the years. When I reversed the steam locomotive to use the two engines as compressors, I CAREFULLY moved the Johnson Bar, keeping clear of it's arc, ( NO power reverse ) and positioned my hand so it would get yanked away. No change in manual operation of Johnson Bar at the low speed while 'working air', it had a counter weight between the frames, and a large coil spring in a tube for normal operation. Piston Valves, Inside Admission. I read somewhere that reversing a slide-valve engine, outside admission, balanced slide valves, with Stephenson Valve Gear could be exciting, and dangerous. I also read, that in 'the old days', if an engine was reversed with the throttle closed, the back air pressure, depending on Johnson Bar position, would spring the latch on the throttle and it would hit the Engineer in the face. I do not want to find out!!! Thank You. I was reading an a account recently of the British steam locomotive 'Blue Peter' which 'lifted' water from a too-full boiler into the superheaters while starting a train in the rain. The thusly-generated steam spun the drivers up to 130 MPH? ( Video from train on YouTube. ) and the Engineer on the footplate was injured from trying to bring the locomotive back to centre-gear. Photos on Internet of damage done to rods. I also wondered if it would be safe to move the engine to centre gear at high speed with tonnage if the throttle stuck open on the road. What WOULD happen?? On a coal burner on the road the fire would be very hot and what was drawn thru the tubes would go down thru the nozzle in a much hotter condition than when drifting downgrade, blower on, throttle closed. ( A Hostler story, here. This one Hostler was lazy and hated running steam engines beyond the points in a trailing-point switch move, stopping, getting off, walking back to the switch stand, setting the new route, walking back to the cab, and backing up. With another Helper in the cab to watch over things the first time, he approached the switch at low speed, shut the throttle, reversed the engine going forward, and reopened the throttle slightly as the engine started over the switch. He jumped from the moving engine going forward at the switch, the engine rolled against the steam from the slightly-open throttle to beyond the switch points, and stopped. He threw the switch for the other track, the engine, of it's own accord then reversed and came back to him. He reboarded and carried on at the throttle in reverse. Strange things done on the Divide, far from supervision. ) From what I understand, in Steam Locomotive 'wood burner' and 'link and pin' days before air brakes, one way to hold back and stop the train was to reverse the engine on steam. I understand, before lubricators in the cab, or mechanically-operated on the steam chests, the Fireman would carry a Tallow Pot with a spout, of hot oil, kept heated on a shelf above the firebox door for the purpose, and walk to the front of the locomotive on the running boards while in motion. The Engineer would watch the Fireman, and on signal, shut off steam. The Fireman would open a petcock on the top of the valve chest, and, with the suction, pour in hot oil above the slide valve, outside admission, for lubrication. He then would shut the petcock and the Engineer would work steam again. The Fireman would cross over to the opposite valve chest, the Engineer looking out that side, as cabs were tiny, back then, and repeat the procedure. If there was a cab war going on, the Engineer might open the throttle before the petcock on the valve chest was closed, ( OOOPSIE! ) and spray hot oil all over the Fireman. ( In steam days here, an Engineer and Fireman would get to arguing and fighting in the cab. Poor Trainman on a freight, and a white line would be chalked vertically down the backhead and thru to the tender to indicate just who's side of the cab was who's. Brotherhood, as the Diesels came. ) If a wood-burner-era locomotive was stopped for any length of time, they would have to grease the rails and slip the drivers on purpose to operate the piston water pump connected to the crosshead to add water to the boiler. Water pump on a steam boat driven off the crosshead in the early days, before Injectors developed. On engines, at night, with oil-burning headlights a flat sheet of tin was moved in front of the headlight lamp to 'Extinguish' the light at meets, or when in the clear or other reasons by the Rules. Some engines had a sort of roller blind to accomplish this purpose. A friend here has a Stationary Engineer's Ticket and ran the large power house at the big mine here before it closed. Compressed air for mine usage, motor generator sets for trolley voltage on the haulage, small GE electric steam boiler. There was a Pelton Wheel on a 36-inch wood stave pipe from the Company dam upstream, but, it was no longer used. Most of the compressors were Ingersoll-Rand c. 1900 and resembled big steam engines as used in mills, but, were driven by large 1000 HP AC electric motors on the crankshaft betwixt the cylinders, one machine with one low pressure at about 48 x 36 inches, a water-cooled intercooler across to a high pressure cylinder about 30 x 36 inches. Both cylinders water-cooled, and loaded and unloaded in stages, causing the machines to gallop and lope at times. Anyway, there were other more-modern vertical 3-cylinder compressors similar in design to ship engines. The outlet manifolds were all burnt and scorched on these. The Engineer said the compressors ran so hot under load when the mine was using maximum air for drilling, that the lubricating oil carried over would burn in the compressed air on exiting the cylinders. Retired stationary fire-tube boilers were outside as additional air receivers. Of a Sunday, when he was the only man on duty, I would go up and walk around with him as he tended the machines, feeling bearings, oiling piston rods and crosshead guides and kept an eye AND an ear on things. If more or less air was needed, he started, or stopped the compressors as required. Cheaper for the Company to employ Engineers at the end than to apply instrumentation as the ore body ran out. They had two locomotive whistles on the roof, on air, to communicate signals to the plant regarding fire, emergency, problems underground, shift changes, but, these had become redundant with radio and improved telephone circuits.) On a steam locomotive, if there was a lot of vacuum into the exhaust nozzle in the smoke box, it would carry over cinders into the valves and steam cylinders, or, worse yet, sand from 'sanding out' the tubes on an oil burner. ( Now, if you were drifting, you would have the Blower on to pull air through from the fire and that might help lift errant cinders or sand up the stack, instead. If you were drifting a long way, you might open the throttle a crack to have the steam carry oil thru for lubrication. When in doubt about lubrication, I have used a long-stem oiler to pour valve oil down thru the relief valves. ) We removed several 'gallons' in a bucket, of sand from the smoke box on oil burners during boiler washouts, there being two wash out plugs at the bottom of the front tube sheet. At the top of the smoke box facing the firebox there was a vertical 1/2-inch metal baffle to force the heat and combustion gases down and then up around the nozzle and into the petticoat pipe and up the stack. The firebox side of the baffle was pitted similar to the outer surface of a golf ball, but, concave. If sand or cinders were left in the smokebox over winter, if wet, they would set up corrosion of smokebox shell with chemicals in soot/cinders. One neat thing we used to do, at lower speeds, was go out and lie on the running board, or sit on the front steps to the running boards of the locomotives when running, peer over the edge of the running board, and watch and listen to the exhaust beat working, or, the relief valves when drifting. You could also watch the 'Motion' and the crosshead and the spring rigging as the engine rode the joints and as the lead drivers and axle slammed back and forth against the hub liners in turnouts and curves. There was enough room to put a piece of plywood on the frame rails under one of the locomotives, above the brake rigging, between the second and third driving axles, just below the burner, and ride in there watching the leaf springs and their linkages and the spokes, rods and counterweights flash by on the outside, but, never got around to doing it. Poor place to be if something went wrong. But.. Learned a lot, and had fun! Much more to learn, too! Idle thoughts from a long life. Hope it is not too boring nor rambling. Thank You!!

[JamesP]

Good discussion!  Kootenay, that is pretty much how my smaller steamers react.  But for the sake of clarification, I do want to address a couple of points that Mark brought up.  Hopefully, I can shed some light on my logic behind my statements.

Mark said, "I disagree that the cylinders would "act as a pump, drawing in exhaust fumes and trying to pump them back into the boiler . . .". When the engine was reversed steam was still supplied to the cylinders which would prevent this. This would be no different than running the engine in reverse which of course was routinely done for long times and distances."      I agree that running an engine in reverse isn't a problem - the steam engine itself operates equally well forward or backward, not withstanding pilot or trailing truck geometery.  However, I was talking specifically about a locomotive that is moving forward with the valve gear in reverse.  Under this condition, the locomotive will certainly draw a vaccuum in the exhaust while building a pressure in the admission side.  It is different than the locomotive actually running in reverse, because the engine is rotating in the wrong direction, so it is trying to suck air in the exhaust and blow it out the admission.  With the cylinder cocks and throttle closed, it will soon build enough pressure to close the snifter (or drifting) valves - more on them in a minute - and start building pressure in the drypipe.  Unless the cylinder cocks are opened or the Johson Bar moved to the proper direction of travel, the pressure will build to a point where it will overwhelm the traction of the drivers, causing them to slide, or stop the train if the speed is slow enough, train weight is light enough and there is enough traction.  The reason why I phrased my initial response as the engine "trying to pump them back into the boiler" (referring to exhaust gasses) is because in reality the boiler pressure would be more than enough to cause the drivers to lose traction before an engine moving forward with the Johnson Bar in reverse could ever pump up enough pressure to actually do that.  My bigger steamer will stop a train without admitting any steam to the cylinders just by reversing the valve gear... and when the valve gear is put back in forward motion, there isn't any doubt that the engine has pumped up pressure in the drypipe, just like Kootenay experienced.  Now, I don't normally stop trains in that manner - if I'm reversing, the cylinder cocks are open, the throttle is cracked to supply positive pressure, and the stopping power varied with the Johnson bar position.  This keeps from forming a vaccuum in the exhaust, and keeps soot from being sucked into the valve and cylinder.  A steam engine can be used to pump air, and reversing the valve gear while forcing the engine to rotate in the same direction will reverse the movement of the air through the engine.  Whew... I realize that was long... but stick with me!

Now, drifting or snifter valves... Mark said, "All the steam locomotives I am familiar with had drifting valves which opened automatically to equalize the pressure on both sides of the pistons to prevent them from pumping air when the throttle was closed. I can't recall if the drifting valve could be manually over ridden but if that was possible, this would be a more effective means of braking that reversing."     Yes, Mark is exactly right that steamers have drifting valves.  These are basically a big check valve on the steam chest, or drypipe side of the valve.  I think that my copy of Grimshaw's "Locomotive Catechism" describes their purpose and operation best:

"Q.  What prevents air and cinders being sucked into the steam chest through the exhaust pipes, when steam is off, and the piston working?"

"A.  A relief valve in the end of the steam-chest, opening inward into the chest, and permitting air to enter the chest through it, instead of coming by way of the exhaust pipes and drawing cinders therewith."

"Q.  When the engine is drifting , what is the danger unless specially prevented?"

"A.  That hot gasses or cinders are drawn into the cylinder, the lubricating oil carbonized and the pistons caused to knock."

So, when steam pressure was absent from the admission side of the slide (or piston) valve and the locomotive was still moving, the drifting valve would open allowing clean air to be pumped through the engine and out the exhaust.  The drifting valves take very little pressure to close, reversing the engine while it is moving forward at speed will easily provide enough pressure and volume to cause them to close.  They are not manually operated, they are just a type of check valve.  Again, on my big steamer, they will close just by reversing the engine while it is moving forward due to the pressure that the engine is pumping up on the admission side of the valve, with a vaccuum being pulled on the exhaust side.  They are basically out of the picture when attempting to stop a train by reversing the valve gear.

So, I know that is a long post... but the events happening in the locomotive when "reverse braking" are somewhat more complicated than it looks like at first glance.  And Mark, please don't think I'm attacking you or anything like that... it's not like that at all... you brought up some good points, and we all can have an enjoyable discussion about these ideas and experiences that all have posted.  I enjoyed reading your post and just wanted to give some clafication to my thoughts.  I also enjoyed reading Kootenay's post about his experiment with braking in reverse using a full size train.

Using the Johnson bar to stop a train might have been OK before air brakes, when speeds were slow and trains were small(er), but I think that we can all agree that it wasn't a common or accepted practice after the implementation of air brakes.

Sincerely,

James

[Kootenay Central]

Thank You.

[KCSfan]

JamesP

The problem with braking by reversing for long periods of time is that the cylinders actually act as a pump, drawing in exhaust fumes and trying to pump them back into the boiler, or at least out the cylinder cocks.  Sucking the abrasive products of combustion (soot, carbon, ashes, etc) into the cylinder could and did cause excessive wear on the cylinders and valves. 

 - James

Braking a train by reversing is ineffective and a definite no - no though I'm sure it was tried in cases of extreme emergencies when the train brakes failed. When reversed the drivers would simply spin wildly and the slippage would result in loss of traction making even the independent engine brakes ineffective. In the days before power reversers the Johnson Bar was almost sure to result in broken bones when attempting to reverse the engine at anything but the slowest speed.

I disagree that the cylinders would "act as a pump, drawing in exhaust fumes and trying to pump them back into the boiler . . .". When the engine was reversed steam was still supplied to the cylinders which would prevent this. This would be no different than running the engine in reverse which of course was routinely done for long times and distances.

All the steam locomotives I am familiar with had drifting valves which opened automatically to equalize the pressure on both sides of the pistons to prevent them from pumping air when the throttle was closed. I can't recall if the drifting valve could be manually over ridden but if that was possible, this would be a more effective means of braking that reversing.

Mark

[KCSfan]

JamesP

The problem with braking by reversing for long periods of time is that the cylinders actually act as a pump, drawing in exhaust fumes and trying to pump them back into the boiler, or at least out the cylinder cocks.  Sucking the abrasive products of combustion (soot, carbon, ashes, etc) into the cylinder could and did cause excessive wear on the cylinders and valves. 

 - James

Braking a train by reversing is ineffective and a definite no - no though I'm sure it was tried in cases of extreme emergencies when the train brakes failed. When reversed the drivers would simply spin wildly and the slippage would result in loss of traction making even the independent engine brakes ineffective. In the days before power reversers the Johnson Bar was almost sure to result in broken bones when attempting to reverse the engine at anything but the slowest speed.

I disagree that the cylinders would "act as a pump, drawing in exhaust fumes and trying to pump them back into the boiler . . .". When the engine was reversed steam was still supplied to the cylinders which would prevent this. This would be no different than running the engine in reverse which of course was routinely done for long times and distances.

All the steam locomotives I am familiar with had drifting valves which opened automatically to equalize the pressure on both sides of the pistons to prevent them from pumping air when the throttle was closed. I can't recall if the drifting valve could be manually over ridden but if that was possible, this would be a more effective means of braking that reversing.

Mark

[BaltACD]

Extensive use of the Independent Brake on a steam engine could cause overheating of the driver tires.  Since the driver tires were shrunk fit on the center part of the driver, overheating could cause the tire to expand and come lose from the wheel center...creating BIG problems.

Car wheels do not have tires shrunk fit on wheel centers as the wheels are all one piece and can withstand much more heat than the tires on engine drivers can.  Car wheels are shrunk/press fit on the axles so it is possible under extreme circumstances for a wheel to heat enough to dislodge the wheel from it's fitment on the axle.

[JamesP]

Yes, this does actually work and was used at times.  However, I have read of at least one railroad that prohibited the use of reverse for braking purposes, while there were others that added appliances to make it more effective.  The problem with braking by reversing for long periods of time is that the cylinders actually act as a pump, drawing in exhaust fumes and trying to pump them back into the boiler, or at least out the cylinder cocks.  Sucking the abrasive products of combustion (soot, carbon, ashes, etc) into the cylinder could and did cause excessive wear on the cylinders and valves.  Also, the fire's exhaust fumes are considerably hotter than the steam, and caused overheating problems in the cylinders, breaking down the lubrication.  The cylinders also weren't receiving proper lubrication while "braking" in this manner, anyway.  I don't have the reference in front of me, but I do remember reading about a device that injected water while braking in reverse to keep the cylinder from overheating.  One other problem on slide valve locomotives without power reverse was unlatching the Johnson Bar to move it from reverse back to forward while the engine was in motion... with the lack of lubrication during the braking, combined with the breakdown of oil due to the ingestion of hot exhaust gasses, the slide valves didn't want to slide very well - unlatch the Johnson Bar and it would move violently and unexpectedly under these conditions, usually injuring the engineer!  As a side note, the lack of proper cylinder lubrication in the early days of steam could cause this problem anytime, which is why many engineers of the era would just set the Johnson Bar and leave it, running the engine by throttle alone, wasting fuel and wearing out the fireman!  Such engineers were nicknamed "rappers" - not exactly a term of endearment from the bakehead.

With the advent of air brakes, it seems like the practice of stopping the train by reversing was discouraged in general.  However, the technique - used carefully - does work.  On my live steamer, I do this with the cylinder cocks open, using the throttle to vary the braking effort.  By keeping steam flowing into the cylinders, at least some steam is still being ejected from the stack, which means that the exhaust isn't being drawn backward into the cylinders.  However, it is a lot different stopping a small locomotive from a very slow speed over a short distance as compared to a prototype locomotive descending a long grade for a long period of time!

 - James

[henry6]

The engine had an independent brake but the engineer could control the length of the stroke of the cylinder with the Johnson Bar.  Reversing the engine per se was not an elective in normal train handling but the reverser (changing the direction) was known to be used in emergencies.  If retainers were to be used on a hill, the train would be brought to a stop and the retainers set up on selected or all cars (and train stopped at bottom of hill and retainers returned); this could not be done while running.  Setting brakes by hand was a way of doing things, yes, but before there were air brakes. In other words, it was not exactly like it is in a diesel or electric locomotive.  And the advances in the air brake system also plays a part in how things are done today....

[pajrr]

Hi Everyone, I have a question regarding train handling with steam locomotives, specifically on a down grade. I know that brakemen would set retainers to keep brakes partially on. Could the engineer also apply slight reverse power using Johnson Bar, throttle and cylinder cocks? Theoretically this would set up a cushionioning effect in the cylinders. Was this method actually used? Thank you in advance