It has been a while since I have been involved in a good discussion about engines/mechanics, and I recently heard a story great to start such a topic.
I grew up in Mt. Olive, Illinois, and my parents still live there. For those of you unaccustomed to Central Illinois, it is about as flat as you can imagine (they don’t allow high-powered rifles there it is so flat).
Anyway, a good friend of my Dad’s and a good rail fan told my Dad that he heard on his scanner that a traction motor burnt out in a two-unit heavy train on NS’s old Wabash main from St. Louis to Decatur. The scanner indicated that the train could only make 5-to-10 mph, so the train was ordered to take the siding around Raymond, Illinois—which is a good 20-25 miles from Mt. Olive.
My Dad’s friend went out to watch the train go by in Mt. Olive, and he said you could really smell the burntout motor.
Two questions:
(1) How does a traction motor burn up in the flatlands of Illinois? I thought they only burned out in Mountains. My basic understanding (and admittedly amateurish is burnout occurs from going below a certain speed for too long).
(2) Wouldn’t hauling a train for several 10s of miles at 5-10 mph also burn out the traction motor on the remaining unit?
DC series-wound traction motors burn out at low speed when they draw too many amps for too long; e.g., throttle in Run 8 at low speed. From the situation you describe, the train was underpowered and since downstate has some rolling hills, even a relatively easy grade could cause problems.
Another probelm could have been a busted gear on either the pinion shaft or the bull gear and the motor oversped and came apart that would also cause the motor to burn out.
Some traction motors also flat out fail because of accumulated overheating episodes over time have weakened the insulation of the motors windings thus permitting arcing and utlimately motor failure. Traction motors are electro/mechanical items that have a practical life expectancy…railroads generally use their equipment to the point of failure before attempting repairs.
Gabe,
Ever burn up a power tool, like a drill or power saw?
Or a electric weed eater or blower?
Notice the blue sparks from the brushes, where they have shorted over and are grounding out…
Same thing can happen to a D/C traction motor…its pretty much the same kind of motor, just a lot bigger and stronger.
Get dirt in there, or have a brush break or ground out, from heat, over loads, and just plain wear and tear, and its done for.
The good part is they are realitivity easy to repair…(relative to the size, of course)
Keep in mind these things get pushed to the max every day, for a million miles…and having one “burn out” is not as common as you would imagine, but it happens.
And the smell is the same as a burnt out power tool, just a bigger stink!
Railway traction motors amaze me. These machines have to endure everything that mother nature dishes out from moisture to temperature extremes. A motor also has to stand up to the pounding from rail joints, switches etc. Bad joints are like dropping the poor thing out of a second story window, I am impressed that they run at all. The most impressive is the fact that the average life of a traction motor is around 5 years!
Randy
Five years! That is it? Don’t get me wrong, from your description, that is impressive. But doesn’t it cost a lot to replace one? They have to haul an engine in the shop and dismember it every five years? That sounds really expensive.
By the way, nice to hear from you again, Randy.
Gabe
P.S. In relation to heat, it was 102 degrees on the day that the engine overheated. And, if you know anything about central Illinois, it was 384% humidity.
Not dismember, Class I railroads have standby trucks already equipped with traction motors and with wheels at the right flange profile and free of flat spots in order to change out the whole truck if any of these problems, tracktion motor burnout, flat spot(s), flange profile not passing inspection (usually two thin), shipped flanges, any of these will bring a locomotive into the shop, disconnet the motor leads and brake rigging, (or hoses to truck-mounted air-brake cylinders) and just lift up the locomotive by the frame and roll under an overhaudled truck and reconnect everything. It isn’t simple, but it is a lot simpler than dismembering.
Replacing the diesel itself or the alternator or generator is more complicated, indeed.
I imagine on some short lines, it is necessary for the locomotive to be idle while the motor on the truck is replaced.
Locomotives rarely go bad at the truck shop. In fact if one traction motor goes bad it will be changed out as soon as possible, at any location. Wheel wear is another issue that is more predictable. At each periodic inspection wheel measurements are done and small wheels are noted. At that point the locomotive may be sent to the backshop for new trucks. I certainly would not shop a unit for trucks unless it really needed trucks.
Randy
Which railroad, Randy? The shops with mechanized lifts can replace a truck quicker than changing out the motor, and the important thing is to get the locomotive back on line as quickly as possible. It would depend on what can be done fastest at the particular shop. Which shop are you at? And I did not say new trucks. Reconditioned trucks, of course.
Possibly at your shop it is possible to change out a traction motor without lifting the locomotive off its trucks? Or at least the one particular truck? I don’t doubt that it is possible, but I would like to know how?
Most Railroads have a drop table. Depending on the size of the wheels it may not be possible to change just one truck. You cannot mix big wheels with little wheels. Changing a single traction motor combo, even if you have to jack the locomotive is much quicker. The only reason to change trucks is for BO wheels, worn brake rigging or more than one bad traction motor. Even a reconditioned truck with new wheels and rebuilt traction motors is not cheap. It will take 2 men about 160 hours to recondition a set of trucks. That translates roughly into $12,480.00 for labor and around $4000.00 for pins and bushings, add $5000.00 for each wheel set (the actual wheel prices are going sky high lately) and add about $7500.00 for each reconditioned traction motor. That makes a grand total of $91,480.00 for the reconditioned trucks. Not something that I’m going to throw around lightly.
Randy
You are correct. The knowledge I have is that most railroads to have spare trucks with traction motors for large fleets of duplicate modern locomotives. So, when one traction motor goes west, a spare truck replaces the truck with the bad motor, and then the motor can be replaced in the truck while the locomotive itself is returned to service, without waiting for the replacement motor to be installed. This would only apply to large fleets of recent design where maximum availability is important. Also, this minimizes the amount of shop space occupied by locomotives. I don’t doubt, however, that some shops do it the way you described, with the same truck being returned to its position with a new or reconditioned motor installted. But this does keep the locomotive out of service for a few hours more. Perhaps even a day.
I also have seen shops with both overhead cranes and drop tables available. Whe a locommotive is “dismembered” (really undergoes heavy repairs), it usually sits on shop trucks, which lack motors and much else but should allow the locomotive to be moved. It is not at all certain that the locomotive will get back exactly the same trucks the were under it when it entered the shop.
I have already picked up 6 deffects on my scanner recently. I say that these engines are just getting to weak to pull this heavy stuff. Two recent trains really astonished me, because they had a backward SD50 on one pulling nearly 150 auto racks that were loaded and a SD40-2 pulling about an 119 car manifest. This does tell me that they are improving though. Although I still would like to see quite an array of units up front even if they are powerful enough to pull it by themselves. [:D][8D]
Hey gabe, once when I used to work in Amtrak’s Wash., DC engine house, I had the oppertunity to see a really fried traction motor from an AEM7. The engine’s t/m actually caught fire in New York, but they didn’t have a drop table to fix the problem, and the Wilmington shops at the time were packed full with b/o stuff also. So management made the decision to deadhead the unit to us in DC. The crew started out one late Friday afternoon and didn’t reach DC until that late Sunday night. Since I used to work the night shift, the t/m change out landed in my lap. I’ll tell you, the paint on the t/m was completely burned off, the internal wiring was all blown out and the paint on the gearcase also was burned away. I’ve seen the result of ‘flash over’, but nothing like what this t/m went through. ‘Flash over’ occurs when there is a build up of metal dust either in the armature or where the commutator is. Anyway, as a joke, I wrote on the b/o slip where it has ‘cause of defect’, I wrote down, ‘Reactor core meltdown’. I and my coworkers(even some of the management) thought is was funny.
GLENN
A R E A L RAILROADER!!!
A R E A L AMTRAKER!!!