Actually in those , they

Actually in those , they appear to be just putting an idler in , so they can drag/limp it back to the shop and do the work.

If you have a problem with wheel or a flange or even a bearing , you can't necessarily ignore it till you get back to the shop. If you can't make temporary repairs , then you either have to pick it up and set it on a flat, or cut it up in situ.

I have seen them cut up whole locomotives on a siding with a plain old rubber tired cherry picker and a cutting torch , they hauled it out on 3 flat bed semi's to the local scrap yard .

Flat spots

In one case I happened across video of, the reason for doing the swap in the field was apparently flat spots on the wheels.

The first video in the series of 8 (links to others in the video’s description): 

(I put the video in as a link not an embed due to the need to see the video’s description to get the other 7 parts.)

Idlers

In the second video you can see an idler axle in front of the engine so it appears they were removing a traction motor and replacing it with an idler.

If the armature of the traction motor fails it can lock up and will slide the wheel, causing flat spots.

The locomotive is then moved dead in tow to a shop where it is actually repaired.

Size is relative

Hi,

it seems this is more a case of "size is relative" rather than being disinclined to make a big repair in the field...

Question is, what are the alternatives. Assuming an axle is damaged and the engine (or car) cannot continue.

• take the loco apart (at least take it off the trucks so it can be moved on a heavy-load flatcar)
• replace a full truck assembly
• put the loco (or one side of it) on rollers so it can be towed
• replace one axle (idler or motor, doesn't matter)
• assuming that the loco is worth enough to not scrap it

Looking at that list, replacing an axle does seem to be one of the easier options... (all of these seem to require some lifting)

However, I have seen a flatcar with roller trucks that would be used to tow a locomotive whose axles are badly damaged. I've also seen a loco from afar that was on replacement trucks for shipping (a narrow-gauge loco being towed to a harbor so it can be shipped. The real trucks were on a flat car further back in the train.

May I assume that the decision on how / where to repair a loco may be largely influenced by the availablility of heavy equipment (e.g. whether a crane is readily available). I've seen videos where locos and cars are moved by using A-Frame crawler things - there seem to be enough of them around so that an axle can be changed in the field...

Have fun!

PS: for re-railing locos and cars, they used "rerailing frogs" in the steam age. They used hydraulic jacks for a long time. Now, it seems, Deutsche Bahn needs to bring out TWO large rail-cranes for a simple derailment. Which takes a full day just for the cranes to arrive...

Defects

In N American practice, this is only done if the frame, structure of the car is so badly damaged that is unsafe to move on its own wheels.

Very common, generally use a "shop truck" that may be painted a bright color.  Car goes directly to the next RIP track for replacement with the correct truck.  Only done if the truck frame itself was damaged.

Generally not done in N American practice, at least not for any road movement.

Most common repair if its a wheel, axle, journal, motor defect.  Generally if its out on line they just put in an idler.  If its in a yard they might replace the traction motor.  The issue with installing a motor is that you have to have the proper type of motor.  That can take days or weeks to acquire and ship to the location.  An idler axle is quicker to install and then you move the engine to the place that has the motor (which also has all the tools and testing equipment to make sure the job is properly and safely done.

Generally a worst case scenario that involves a major wreck, collision or derailment.  Would be extremely rare to be the outcome for a mere wheel defect.

Record time

We had a team on the Marysville Sub who could change out an axle under a freight car, on the main track, in less than 30 minutes.

Re Record time

Hi Dave,

That Marysville crew sound like the railroad equivalent of a F1 pit crew. They know their stuff and have their act together. 

N Platte Yard

At the UP N Platte Yard they have all the inbound empty coal trains pull through a small shed where their wheels are ultrasonically test for defects as they roll through.  It is affectionally known as the "crack house".  When the train gests into a track a special crew can change out any defective axles under any car, in train without uncoupling or even breaking the train line, in less than 30 minutes.

They actually did benchmark NASCAR pit crews.

N Platte Yard

At the UP N Platte Yard they have all the inbound empty coal trains pull through a small shed where their wheels are ultrasonically test for defects as they roll through.  It is affectionally known as the "crack house".  When the train gests into a track a special crew can change out any defective axles under any car, in train without uncoupling or even breaking the train line, in less than 30 minutes.

They actually did benchmark NASCAR pit crews.

N Platte Yard

At the UP N Platte Yard they have all the inbound empty coal trains pull through a small shed where their wheels are ultrasonically test for defects as they roll through.  It is affectionally known as the "crack house".  When the train gests into a track a special crew can change out any defective axles under any car, in train without uncoupling or even breaking the train line, in less than 30 minutes.

They actually did benchmark NASCAR pit crews.

N Platte Yard

At the UP N Platte Yard they have all the inbound empty coal trains pull through a small shed where their wheels are ultrasonically test for defects as they roll through.  It is affectionally known as the "crack house".  When the train gests into a track a special crew can change out any defective axles under any car, in train without uncoupling or even breaking the train line, in less than 30 minutes.

They actually did benchmark NASCAR pit crews.

N Platte Yard

At the UP N Platte Yard they have all the inbound empty coal trains pull through a small shed where their wheels are ultrasonically test for defects as they roll through.  It is affectionally known as the "crack house".  When the train gests into a track a special crew can change out any defective axles under any car, in train without uncoupling or even breaking the train line, in less than 30 minutes.

They actually did benchmark NASCAR pit crews.

Re: N Platte Yard

The "crack house" name breaks me up.