I'm farely new to this hobby and I can see why it can be addictive. But I have questions, mostly from actual observations locally as well as watching youtube videos.
Why do some locomotives use the bell when going over grade crossing and some don't? Company policy?
If a train has more than one locomotive and are using both for power, can the lead loco control both? Are they electronically coupled?
As above, why would a loco be pointed the opposite direction? Can they still help move the train or are they put in "neutral" and just towed along?
I'll have more later.... thanks in advance!
Regards - Steve
steve-in-kvilleIf a train has more than one locomotive and are using both for power, can the lead loco control both?
It can, through a system initially developed by Frank Sprague called multiple-unit control. If you look up 'diesel MU' you'll find much more detailed accounts of the details, and the various ways the systems could be provided. Usually the lead locomotive can control more functions than just 'power'.
DPU is a later version of MU that allows control of power that is 'remote' from the lead locomotive's cab.
Are they electronically coupled?
Older versions of the system were electrically coupled (through wires in special cables). Sometimes different systems assigned different wires in a cable to 'non-standard' functions and you'd have to be careful when connecting them. Baldwin and some other systems used air control for the throttle, which had advantages and disadvantages, but could be equipped with a compatible system to run with 'normal' electric MU systems. More modern systems do use electronic components for some of the functionality.
Modern engines are fully bidirectional in terms of making power, with the caveat that if the exhaust 'leads' the cooling fans or radiators in tunnels, there can be a problem with heat. Note that before a consist is put into service, the direction for each unit has to be carefully set to "forward" or "reverse" depending on which way it is pointing -- you may have noticed a little "F" painted on one end; this signifies 'front' for MU setting purposes. Once that is done all the locomotives happily pull together.
On the other hand, it's not uncommon to have engines 'dead in tow' in what looks like a long power consist. Only the amount of power 'needed' to pull the train has to be running, and so either 'isolating' (leaving the engine idling but not producing electricity for propulsion) or shutting down the others may make economic sense.
The direction of the cab is usually chosen for convenience. Many railroads found that two 4400hp units in MU represented a good power choice for dispatched train length, and if you couple these 'cabs-out' you have in essence a bidirectional 88oohp locomotive with some redundancy if one-half has to be derated or shut down. On the other hand, when DPU began to become common you'd see 'elephant' style operation (with all cabs on one end facing forward) so that if the lead locomotive had trouble, it could be taken off and the following cab used to continue running without delay.
It is surprisingly common to see over-the-road trains operating long-hood-forward, even though there can be dramatic headaches for crew in doing so. I most recently saw an intermodal train with all three engines oriented long-hood-forward leaving Memphis eastbound on NS (ex=Southern) day before yesterday. I believe most roads have speed restrictions when power leads this way, although the restriction is for visibility and not because the engine isn't capable of running safely either end first at full power and full speed.
steve-in-kvilleI'm farely new to this hobby and I can see why it can be addictive. But I have questions, mostly from actual observations locally as well as watching youtube videos. Why do some locomotives use the bell when going over grade crossing and some don't? Company policy? If a train has more than one locomotive and are using both for power, can the lead loco control both? Are they electronically coupled? As above, why would a loco be pointed the opposite direction? Can they still help move the train or are they put in "neutral" and just towed along? I'll have more later.... thanks in advance!
CSX Book of Rules 203 - Locomotive Bell and Horn 203.1 Ring the locomotive bell before moving a locomotive that has been stopped one minute or more, and while: 1. Approaching and passing passenger stations, 2. Approaching and passing over public crossings at grade, 3. Moving through tunnels, 4. Approaching persons on or around the track structure, and 5. Approaching and passing roadway workers identified by white or orange hard hats.203 - Locomotive Bell and Horn 203.1 Ring the locomotive bell before moving a locomotive that has been stopped one minute or more, and while: 1. Approaching and passing passenger stations, 2. Approaching and passing over public crossings at grade, 3. Moving through tunnels, 4. Approaching persons on or around the track structure, and 5. Approaching and passing roadway workers identified by white or orange hard hats.
203 - Locomotive Bell and Horn
203.1 Ring the locomotive bell before moving a locomotive that has been stopped one minute or more, and
while:
1. Approaching and passing passenger stations,
2. Approaching and passing over public crossings at grade,
3. Moving through tunnels,
4. Approaching persons on or around the track structure, and
5. Approaching and passing roadway workers identified by white or orange hard hats.203 - Locomotive Bell and Horn
5. Approaching and passing roadway workers identified by white or orange hard hats.
Locomotives are coulpled together to operate in MU or Multiple Unit control. The locomotives are connected with a 27 Pin electrical cable between each unit as well as four pneumatic hoses in addition to the air hose that connects to the braking system of the train they are hauling. When connected in MU control one unit is configured as the 'Leader' by setting the appropriate switches and cut outcocks on all the locomotives. Needless to say, those that are not configured as the leader will be configured to be in trail. All locomtives in the engine consist may be used to power the train, consistent with each company's rules govening how many powered axles may be on line at one time. Most carriers have some limit on the number of locomotives that may be handled in the engine consist of a train. On CSX that number is 12. In many cases locomotives are moved to and from repair shops on specific trains. Locomotives not needed to actually power the train will be handled DIT (Dead in Tow), in the Winter time DIT engines will also have their cooling systems drained as the railroads only use plain water in the cooling systems.
The pulling power of a locomotive is not dependent upon the direction of the cab. They develop just as much pulling power moveing forward or backward - the diesel engine, main generator and traction motors will move in the direction specified by the 'reverser' on the lead locomotive - the reverser is nominally a 3 position switch - forward - neutral - reverse. Part of the configuration in setting up a MU consist is that only the Reverser on the lead locomotive will control the direction of all other locomotives in the consist.
A two unit engine consist with the locomotives running back to back makes things easier for the crews at the other end of the run as the locomotives can operate back to origin without the need to be turned to get the operating cab on the lead for the return trip.
Never too old to have a happy childhood!
steve-in-kvilleIf a loco is DIT, is there a way to disconnect the traction motors to avoid un-necessary wear?
Steve: Welcome aboard!
I hope the folks on here will correct me, but I believe the traction motors need to be electro-magnetically engaged otherwise they will just spin — so they're kinda automatically disconnected.
I believe this is because there are no permenant magnets in the trucks that would cause constant wear for a locomotive that is dead in tow.
Best,
Steve
Steve SweeneyDigital Editor, Hobby
When a locomotive is DIT - it has been configured (with the prime mover shut down or operating) so that no electrical power is being sent to the traction motors - the commutator of the traction motor does revolve as it is geared to the axle upon which it is mounted - there is no electricity working through the traction motor.
The only wear is on the ring gear on the axle and the pinion gear on the traction motor. Such wear is negligable.
steve-in-kvilleSo the brakes would be like a semitruck, where they need air applied to move the cars, right? No air and the brakes lock up.... I would imagine.... (you guys are gonna get tired of my questions soon!)
A better description of RAILROAD air brakes than I could ever formulate
http://www.railway-technical.com/trains/rolling-stock-index-l/train-equipment/brakes/north-american-freight.html
The thing to remember - in a train, that is required to have a fully charged air brake system - removing air applies the brakes. Increasing air pressure works to release the brakes and recharge the system.
Yes and no.
In a railway brake cylinder the spring pushes to release the brake. Air pressure applies the brake. If the entire air brake system on a railcar or locomotive has been bled off to 0 PSI the air brakes are released (this is done on a daily basis when cars are switched). Brake cylinder air pressure may take anywhere from minutes to months to leak off completely, but it cannot be depended on for long periods of time. This is why handbrakes (manually applied parking brakes) are needed, nearly every car and locomotive has one.
Locomotive (known as the indpendent brake) and car (known as the automatic) air brakes work slightly differently, and while they are interconnected the Engineer can control them together or separately. Locomotive brakes are straight air, increasing air pressure applies the brake, it's that simple. Cars are more complicated.
A car's air brake system has been designed so that after the system is charged a drop in brake pipe pressure at a rate of at least 3 PSI per minute will cause a brake application. And if the brake pipe pressure drops at a very high rate a emergency brake application is triggered, which involves all the cars applying the maximum air braking effort possible at that point. This is the fail-safe part of the railway air brake system, if a problem occurs (busted air hose, broken coupler, derailment, etc) all the brakes apply automatically and the train comes to a stop.
Understanding why this happens requires a bit more of a detailed explanation of how a car's control valve works internally.
The air brake application depends on the difference in air pressures on two sides of a slide valve, the reservoir and the brake pipe. The two sides are also connected by a small (3/32 of an inch in diameter) passage through which air flows to charge the car's reservoir. The small size of this passage is also why it takes a long (~7 minutes) to fully charge a car that was previously bled off.
Let's start with the car fully charged, both the reservoir and the brake pipe are at 90 PSI. The Engineer moving the brake valve in the cab reduces the brake pipe pressure fairly quickly, so now at the car the brake pipe is at a lower pressure than the reservoir. This difference in pressure forces the slide valve over, which blocks the 3/32'' passage while also exposing the pipe to the car's brake cylinder. When the Engineer moves the brake valve to release this process is reversed, allowing the car's reservoir to be recharged from the brake pipe.
HOWEVER, this system is not perfect. If the brake pipe pressure is reduced at a very slow rate then air will simply flow out of the reservoir through the 3/32'' passage back into the brake pipe, and the pressure stays approximately the same on both sides of the slide valve. As a result the valve does not move over, no air is sent to the brake cylinder and the car's air brake stays released.
This is what happened at Lac-Megantic, where the train was left with the automatic (train) brake released and not enough handbrakes were applied to hold it on a grade, only the straight-air independent (locomotive) brake was applied. With all the engines shut down the air pressure slowly leaked off.
Keep in mind that what I have given here is a very simplistic explanation of the air brake system, and I have left out the emergency reservoir and other portions like quick service, quick charge, retainers, load/empty features, and pressure maintaining etc. Just trying to keep this from getting out of hand initially.
EDIT: Balt posted while I was writing. Al Krug's sites are a terrific resource for this sort of information.
Greetings from Alberta
-an Articulate Malcontent
This is a good site (at least an archive) that has a weath of knowledge.
http://hm.evilgeniustech.com/alkrug.vcn.com/rrfacts/rrfacts.htm
There is a 2 part section on brakes.
Welcome aboard.
Robert
steve-in-kvilleSo locomotives needs air to apply brakes, but cars need a happy balance? I would imagine that a 100-car train would take quite a long time fill all those lines and tanks.
Yes, the engine brake can be controlled separately from the train brakes. Ordinarily, when the train brakes are applied, the engine is also braked--unless the engineer stops that braking ("bails the engine brake off"), and the engine can be braked separately.
As you can see, having the cars braked by reducing the brakeline pressure is much faster that having them braked by applying more pressure in the brake line. Indeed, the reduction in pressure travels much faster through the line than an increase in pressure is able to travel.
George Westinghouse's first brake system was "straight air,"which worked fairly well for short trains, but he soon realized that the genesis of the current system was far superior in braking time, and developed the first version (maany times improved) of the current system..
Yes, it takes time, especially in cold weather, to build the brakeline pressure up in a long string of cars. There are tails of yardmasters or other superior people who insist that a mewly made up train be taken out immediately--and such are instructed in the facts of pumping up.
Johnny
I may be mistaken - but I believe the operation of railroad Air Brakes comprised about two to three WEEKS of the Engineer Training cirriculum at CSX's REDI training center before REDI was eliminated by the PTC putsch at CSX.
BaltACD I may be mistaken - but I believe the operation of railroad Air Brakes comprised about two to three WEEKS of the Engineer Training cirriculum at CSX's REDI training center before REDI was eliminated by the PTC putsch at CSX.
The classroom portion of CN's Engineer training program now takes 3 weeks. Many things are skimmed over and others are not mentioned at all. I am given to understand that at one time new Engineers spent nearly 2 months in the classroom, and older heads were given the opportunity to take additional trainer or refresher courses. None of that happens anymore.
steve-in-kvilleSo if a railcar breaks away, it locks up? Just like trucks with air brakes?
Yes, as long as it was charged with air first and its air brake system is working properly.
Cars that have been bled off or have defective air brakes will continue to roll if they are uncoupled from the train. Yard crews take advantage of this when switching by kicking or humping.
This was the main drawback of Westinghouse's original straight-air system. If anything happened to cause the brake pipe pressure to drop to 0 PSI (busted air hose, broken coupling, derailment, etc) then the train had no brakes, and the tail end could run away backwards. The crew then had to go 'over the top' and stop it with handbrakes.
SD70Dude BaltACD I may be mistaken - but I believe the operation of railroad Air Brakes comprised about two to three WEEKS of the Engineer Training cirriculum at CSX's REDI training center before REDI was eliminated by the PTC putsch at CSX. The classroom portion of CN's Engineer training program now takes 3 weeks. Many things are skimmed over and others are not mentioned at all. I am given to understand that at one time new Engineers spent nearly 2 months in the classroom, and older heads were given the opportunity to take additional trainer or refresher courses. None of that happens anymore.
When I went into engine service 15 years, we started out with one week of classroom training at my home terminal, mostly basic mechanical items. Then a month or so of field OJT, then two weeks of classroom training at Salt Lake City. That was mostly rules and running a simulator. They had a working air brake mock-up, but that probably used up a day or less of the classroom time. After that back to OJT until they felt you were ready to be qualifed. About 6 months total, give or take. Those who paid attention as a conductor to what the engineer was doing, where and when he was doing it had a bit easier time in training. {Most of our modern engines have a duplicate operating screen on the conductor's side. It shows the same thing the engineer sees. At least until that screen was taken out and replaced by the PTC screen.) Some who spent more of their time on inspecting the inside of their eyelids for cracks had it a bit harder.
They seemed to stress the use of dynamic brakes instead of the automatic air brakes in train handling for fuel conservation as much as possible. (I think that may have changed somewhat now.) It was stressed so much that one time I had a student engineer running the train when an approaching train (two main track territory) went into emergency and announced it over the radio about a mile or so from us. The student wanted to throttle down and then go into dynamics. I told him to starting setting some air, we needed to get our speed down and be prepared to stop if that train was strewn across our track. That we didn't have time for the fuel saving way.
You really learned how to use air brakes on the job. Training engineers, backed up by the local managers (Back then they were old head engineers who had seen and done it all themselves. Not young guys with limited field experience who mostly know what the books and their superiors tell them.) made sure new engineers knew how to use air brakes for train handling.
Jeff
Overmod steve-in-kville If a train has more than one locomotive and are using both for power, can the lead loco control both? It can, through a system initially developed by Frank Sprague called multiple-unit control. If you look up 'diesel MU' you'll find much more detailed accounts of the details, and the various ways the systems could be provided. Usually the lead locomotive can control more functions than just 'power'. DPU is a later version of MU that allows control of power that is 'remote' from the lead locomotive's cab. Are they electronically coupled? Older versions of the system were electrically coupled (through wires in special cables). Sometimes different systems assigned different wires in a cable to 'non-standard' functions and you'd have to be careful when connecting them. Baldwin and some other systems used air control for the throttle, which had advantages and disadvantages, but could be equipped with a compatible system to run with 'normal' electric MU systems. More modern systems do use electronic components for some of the functionality. As above, why would a loco be pointed the opposite direction? Can they still help move the train or are they put in "neutral" and just towed along? Modern engines are fully bidirectional in terms of making power, with the caveat that if the exhaust 'leads' the cooling fans or radiators in tunnels, there can be a problem with heat. Note that before a consist is put into service, the direction for each unit has to be carefully set to "forward" or "reverse" depending on which way it is pointing -- you may have noticed a little "F" painted on one end; this signifies 'front' for MU setting purposes. Once that is done all the locomotives happily pull together. On the other hand, it's not uncommon to have engines 'dead in tow' in what looks like a long power consist. Only the amount of power 'needed' to pull the train has to be running, and so either 'isolating' (leaving the engine idling but not producing electricity for propulsion) or shutting down the others may make economic sense. The direction of the cab is usually chosen for convenience. Many railroads found that two 4400hp units in MU represented a good power choice for dispatched train length, and if you couple these 'cabs-out' you have in essence a bidirectional 88oohp locomotive with some redundancy if one-half has to be derated or shut down. On the other hand, when DPU began to become common you'd see 'elephant' style operation (with all cabs on one end facing forward) so that if the lead locomotive had trouble, it could be taken off and the following cab used to continue running without delay. It is surprisingly common to see over-the-road trains operating long-hood-forward, even though there can be dramatic headaches for crew in doing so. I most recently saw an intermodal train with all three engines oriented long-hood-forward leaving Memphis eastbound on NS (ex=Southern) day before yesterday. I believe most roads have speed restrictions when power leads this way, although the restriction is for visibility and not because the engine isn't capable of running safely either end first at full power and full speed.
steve-in-kville If a train has more than one locomotive and are using both for power, can the lead loco control both?
The lead engine in a consist determines direction of the engire consist. Individual engines in trailing postions react to the reverser on the lead engine. The reverser on trailing engines is centered and removed. You don't have to individually set each one up in that regards.
Distributed power consists have a switch (computer soft key) that asks if the direction is same as lead or opposite to lead. This is only on the lead engine of the remote consist. (Remote consists can have multiple engines and our set up like a normal consist. The difference the DP stuff does is transfer the control from the lead remote's control stand to the lead engine of the train.) If this is not set properly, the remote engine(s) will pull in the opposite direction of the head end.
steve-in-kvilleLots of great info, and it begs another handful of questions! Back to the brakes on railcars.... it was mentioned that the air needs to be bled slowly or the care will go into panic mode and into an emergency brake. Can a car be unhooked from the train without bleeding the tanks? Or is that the point of slowly bleeding the air? Maybe I just answered my own question?
It is usually desirable for cars that are being set out to be left with the air brakes in emergency, and of course with sufficient handbrakes applied.
Unless it is very cold, leaving cars or the tail end portion of your train in emergency while switching will not hurt anything. In cold weather this will make it take a lot longer to pump up the train again, and certain valves may also stick open, which will require the Conductor to walk the train to find and fix the problem.
In this scenario it is better to vent the brake pipe air gradually, by separating from the tail end portion and then opening the angle cock (valve at the car's end) slowly. This will result in a full service brake application, not emergency, on the cars being left.
SD70Dude steve-in-kville Lots of great info, and it begs another handful of questions! Back to the brakes on railcars.... it was mentioned that the air needs to be bled slowly or the care will go into panic mode and into an emergency brake. Can a car be unhooked from the train without bleeding the tanks? Or is that the point of slowly bleeding the air? Maybe I just answered my own question? It is usually desirable for cars that are being set out to be left with the air brakes in emergency, and of course with sufficient handbrakes applied. Unless it is very cold, leaving cars or the tail end portion of your train in emergency while switching will not hurt anything. In cold weather this will make it take a lot longer to pump up the train again, and certain valves may also stick open, which will require the Conductor to walk the train to find and fix the problem. In this scenario it is better to vent the brake pipe air gradually, by separating from the tail end portion and then opening the angle cock (valve at the car's end) slowly. This will result in a full service brake application, not emergency, on the cars being left.
steve-in-kville Lots of great info, and it begs another handful of questions! Back to the brakes on railcars.... it was mentioned that the air needs to be bled slowly or the care will go into panic mode and into an emergency brake. Can a car be unhooked from the train without bleeding the tanks? Or is that the point of slowly bleeding the air? Maybe I just answered my own question?
Venting at the angle cock that way is a no-no for us. (Not that it hasn't been done before.) The proper procedure is to use the Handle Off position on the automatic brake valve and reduce the brake pipe pressure to 20 psi. Then leave the angle cock open on the standing cars and cut away. Freight equipment won't go into emergency with that little of air pressure.
That procedure is also supposed to be used when cutting away from cars at the terminating terminal when carmen are going to do an inbound inspection on the cars. One thing they will be looking for is brake piston travel on the cars, an emergency application may (probably will) have the brake pistons out beyond the range of acceptable operation for service braking.
jeffhergert If this is not set properly, the remote engine(s) will pull in the opposite direction of the head end.
Well, not exactly; more precisely they may try to pull in the opposite direction, be 'overcome' by the head-end power (perhaps assisted by gravity), be damaged as a result, and then not be available for power or dynamic braking when expected. One of the famous Canadian 'stringlining' incidents (in 2005?) was attributed to precisely this.
Overmod jeffhergert If this is not set properly, the remote engine(s) will pull in the opposite direction of the head end. Well, not exactly; more precisely they may try to pull in the opposite direction, be 'overcome' by the head-end power (perhaps assisted by gravity), be damaged as a result, and then not be available for power or dynamic braking when expected. One of the famous Canadian 'stringlining' incidents (in 2005?) was attributed to precisely this.
I believe you mean this one:
http://www.tsb.gc.ca/ENG/rapports-reports/rail/2005/r05v0141/r05v0141.html
This article sums it up quite nicely, if one does not have time to read the report:
https://www.theglobeandmail.com/news/national/train-doomed-from-start-tsb-report-finds/article18140320/
So far that retired BC Rail Carman has only been half correct with regard to the abandonment of sections of BC Rail. A few years after the Cheakamus Canyon derailment there was a large washout and/or rockslide somewhere along that line, and it was not repaired for several months. During that time CN seriously considered abandoning the line between Squamish and Lillooet, but eventually decided to keep it in operation.
That would likely have been the first step in the eventual downfall of all operations between North Vancouver and 100 Mile House (with a continuing retreat north if mills close), there is not a lot of freight traffic at Squamish or Lillooet and practically nothing online.
I will copy and paste this to 'String Lining' to avoid going too far off-topic over here.
jeffhergertSome who spent more of their time on inspecting the inside of their eyelids for cracks had it a bit harder.
zardoz jeffhergert Some who spent more of their time on inspecting the inside of their eyelids for cracks had it a bit harder. Are you implying the some Conductors actually sleep on the job? Shirley you jest.
jeffhergert Some who spent more of their time on inspecting the inside of their eyelids for cracks had it a bit harder.
Are you implying the some Conductors actually sleep on the job? Shirley you jest.
Some Engineers do too, and not just when stopped in a siding!
Brings to mind an anecdote from Classic Trains magazine some years ago, about a C&NW commuter train engineer who would whistle for crossings perfectly while 'inspecting his eyelids'. He had been on the same run for years, and obviously knew the line like, well, the inside of his eyelids!
NTSB has numerous reports of Engineers and Conductors performing eyelid inspections - to their own detriment.
Not at all. Some are just "deep in thought".
And don't call me Shirley.
Yes, they will try and usually are overcome by the headend since normally on most trains there is only one engine in the DP position. However, if you put the "fence" up and start out with the DP only, you can tell right away which way it's going. It's happened a few times that the DP was set up incorrectly at the origin location. And travelled a couple of hundred miles before it was caught. I've had some experience in this myself.
About 6 or 7 years ago, I was called to go to Council Bluffs yard and put the Proviso bound manifest together. The engine consist was already set up and the DP placed in the train. All we had to do is double (or triple more likely) the train together, do the proper air tests and depart. This we did. Nothing seemed out of order. It pulled a bit hard where trains usually pull a bit hard leaving the terminal. It was once out on the main line where I noticed the DP was loading eratically. I talked to locomotive maintenance by radio and they thought it was dirty fuel filters.
It wasn't until half way through the trip it became a problem pulling. We stopped for traffic ahead on the ruling grade for the subdivision. It was a very hard pull starting, and thinking the problem was dirty fuel filters that was causing the DP to not load properly, it never occured to me that the DP might not be set up right. (At the time, there was no way to tell on the head end how the DP consist(s) are orientated. Now that option has been added to many, if not all DP operation/control screens.) A few miles away we stopped to pick up a MOP, aka elsewhere as a Road Foreman or Travelling Engineer. I told him of our experiences and what loco mtce said. It acted up and he never thought about the DP orientation being a problem either. He had the conductor, a set-back engineer, run most of the rest of the way to keep his engr's license current.
Upon arrival at the end of our run, a mechanic was there to change the fuel filters on the DP. I also told the outbound engineer of our experiences. About a week later, I met him and he told me that about 50 or 60 miles into his run, he was stopped on level (or as close as it gets) ground. When he got a signal to go, for some reason he decided to start the train using the DP alone. It started going back the way it had come. They got a passing train to stop and get on the unit, and sure enough it was orientated the wrong way.
After that, anytime I board a train at the originating terminal and I haven't put the engine consist together, I check on the DP orientation. Either getting on the DP, checking the DP screen or just letting the DP start the cars once the head end has been tied on. My embarrassment is tempered by the fact that it happened to 3 or 4 other veteran engineers also. One was a train coming out of Proviso and was half way across Iowa before it was caught.
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