These questions are from a person unfamiliar with prototype operations, so maybe someone with expertise can answer my questions. First, I saw a video of a BNSF train with three locos at the head end and an end of the train helper. How does the train driver control the helper so that it doesn’t put too much slack in the couplers? Secondly, the train in the vid lost an air hose (on the head end loco), so how in the heck was the engineer able to stop the train? These may be dumb questions, but I seriously want to know the answers. Thanks G.S.
the remote locomotives are radio controlled from the leading engine. i could explain railroad air brakes to you but you would probably learn a lot more by looking up railroad air brakes on google and then read the wickipedia site on that subject.
grizlump
You have fallen victim to “Hollywood” air brakes where a train or truck runs away if the air is lost. In real life they work just the opposite. Air holds the brakes off so if the air is lost for some reason the train goes into emergency braking. Air brakes on trains are quite complex and work very well.
The air does not hold the brakes off. That’s why the rules require setting handbrakes because, disconnected from the air compressor on an engine, the air brakes will eventually bleed off and release.
An air pipe runs the length of the train, it pressurizes a pair of air reservoirs (air tanks) on each car. Normally there is no pressure in the brake cyliner and the brakes are released. Whent he engineer sets the brakes he lowers the pressure in the brake pipe. When the pressure in the pipe is lower than the pressure in the reservoir, a valve puts air from the reservoir into the brake cylinder and sets the brakes. When he releases the brakes, he makes the pressure in the train line more than the pressure in the reservoir and the valve changes to put air into the reservior and release the air out of the cylinder. When the pressure drops rapidly there is a large difference in pressure between the the train line and the pressure in the reservoir and the valve puts air from the second reservoir (the emergency portion) into the brake cylinder.
On the engine there are two brake systems (maybe three), really two (maybe three) ways to set the brakes. There is the train brakes where the engine operates just like a car in the train, then there is the independent brakes used to stop the engines (normally not the train) and finally dynamic brakes. And engineer can set the train brakes and release the engine brakes at the same time or release all the air brakes and just use the dynamic brakes.
Hello G.S.,
One point that’s been missed in this discussion is that “helper” usually describes a locomotive with a crew. Remote-control units such as those you saw in the video are called “distributed power,” or sometimes “d.p.” units, as in located (distributed) somewhere besides the head end of the train.
So long,
Andy
The Southern Pacific sometimes installed special devices for the front couplers of steam locomotives This held the coupling pin up so that the locomotive’s coupler wouldn’t lock onto the train’s coupler. The device looked a lot like an uncoupling bar, but its middle section was shaped in a flat-bottomed “U” shape. When engaged, the “U” held up the uncoupling bar’s rod holding the pin. With this device, the helper locomotive needed only to slow down and let the train pull away without slowing or stopping.
These devices were used for the short (less than two miles) one-percent grade on the eastward approach (southern end) of the Suisun Bay Bridge on the line between Oakland and Sacramento where grades elsewhere were minimal. They may have been used elsewhere (likely), but I don’t have any information as to where. Since it was used on helpers at the very end of the train (behind the caboose), it would seem only smaller locomotives (like Consolidations which were stationed at Port Costa) would use the device.
Mark
Two different answers about the helper and 3 on the brakes. Which one to follow? Unfortunetly I’m not all knowing or an expert so the most I can do is put out what little knowledge I have and help sort through all this. With the help, look towards the second one. I’ve heard of seperate terms before to describe a “helper” engine that had a crew on board and a “helper” that was radio controller. Just a side note on this one the National Rail Road Museum uses an old ALCo S6 for the train rides during the summer. It’s an old Green Bay & Western switcher that was used by Georgia Pacific around the factory and was converted to radio control. It was kind of neat how the engineer at the museum was explaining how the boxes in the cab and antenna’s were used so a conductor could walk along side the engine and operate it outside. The museum converted it back to in-cab control for there use, but the antenna’s and all the computer boxes are still there although one of the former operators kept all of the actual computer.
As for the brakes, I can tell you how air brakes on a semi work, but that doesn’t help here. What I can tell you is I know part of it works the same. If the brake system looses air pressure (such as the disconnected hose) an emergency system is in place to apply brakes. In other words go by the post that was right before mine.
But if you get the chance do come to NRRM here in Green Bay, WI. It’s cool, they do move stuff around a bit too. Right now a few of the engines they had outside are across the street sitting on a siding next to a pretty big company. The steam roster doesn’t change, but then again how would you move around a 1 000 000 plus pound Big Boy outside just because it’s a nice day out. The museum does restore old cars and from I’ve come across some diesel engines too, but the diesels seem to go slower. They do have a few cool ones out in the “yard” as I like to call it. The
Thanks for all the info guys. I should have thought about emergency brakes as the train stopped within a few hundred feet from a pretty rapid speed. Milw-rodr, I’m in Ft. Gratiot, Mi., so would be a bit of a hike to visit the museum. I do have the opportunity to railfan the CN/GTW here at their classification yard just West of the Port Huron/Sarnia tunnel though. I am, in fact, modeling in HO the same from the tunnel to the former auto factories in Flint, Mi. Again, thanks to all who responded. G.S.
If the train stopped within a few hundred feet, either the speed wasn’t very rapid or Hollywood was at work again! Even in full emergency, a train heavy enough to need distributed power would need several thousand feet to stop on anything except a really steep upgrade.
Folks used to the stopping power of rubber on the road just don’t seem to grasp that a modern freight car only has the equivalent of eight short chalk lines of steel-on-steel contact to transmit braking force from the wheels to the rails - and may weigh in excess of 100 tons. Think big steel toboggan.
The ore train that ran away and crashed on Cajon Pass some time back actually accelerated downgrade after the helper engineer hit emergency!
Chuck (Modeling Central Japan in September, 1964)
Ah but see then you get to hop on the S.S. Badger and take a nice ferry ride over. I mention this because the Badger was originally built as a RR ferry between WI and MI. Just be preparred for a ride. It took us 4 1/2 hours to cross Lake Michigan and I doesn’t get any faster. I wish I was older though cause then maybe my parents would have let me go around and explore more places. Heck I wanted to go to the captain and see if I could get a ship tour. Which would have been neat since the Badger was still boiler operated. But there is one glitch. The company that does the Manitowoc WI to Lansing MI ferry crossing bought a much faster, and larger, catameran type ferry a few years ago. It does the crossing in a few hours. More vehicles, more passengers (the boat is built as a passenger/car ferry, not just vehicles), and half the time. Actually hold on I’m going to check because they started building these new ferrys to take over…Yep ok they still use it. The company sort of gave everyone the impression that with the addition of the one faster/bigger ferry they were going to get another and retire the Badger but they didn’t. If you go to http://www.ssbadger.com it’s all there. And just in case anyone was wondering if you click on the ship tour and took at the lower map we spent our crossing in stateroom 9 or 7. Close enough if we wanted we could have got out the window and walked to the bow. And yes, I did go to the back and watch all the vehicles get driven on. Come on, I was only 11 or 12, but then again even if I did this again this summer I would run to the back and watch all the vehicles drive on. Oh, and by the by in 10 days the S.S. Badger will be celebrating 56 years of service.