Working rail roads and their tracks.

[ArlyA]

On one of the railfan sites (YT) they sometimes upload really long trains with engines in the middle running. I tried to find one recent one but now can't find it.

Edit, I found it
5~1~2~1 Engines, 322 Cars! Kearney, NE 3/2/22 1:18cst - YouTube

Yes, they has 2 power units in the middle and one at its end. Thanks!

 

[Cub 7274]

I've seen quite often an engine in the middle of a train. Is that what you are referring to? What is the benefit of that?

It is called distributed power usually to help the head end units and controlled by the leading unit- sometimes the distributed power would be cut off with the remaining cars to form a new train for another destination...

 

[aczlan]

It is called distributed power usually to help the head end units and controlled by the leading unit- sometimes the distributed power would be cut off with the remaining cars to form a new train for another destination...

It also helps keep the middle of the train from trying to cut across the curve on a large curve.

Aaron Z

 

[ArlyA]

It also helps keep the middle of the train from trying to cut across the curve on a large curve. Aaron Z

Not so. You do know there are pig tail corners out there? No engine in the middle is require to do them.

 

[dodge man]

A little off topic but train related. A few years ago we took Amtrak from Burlington Iowa to Denver Colorado. The train continued to California. The train was a 2 or 3 hours late on the way to Denver but was something like 10 hours late going home. The conductor sat down across the aisle from me and we talked for several minutes. He said the trains couldn’t go as fast through the mountains when it was hot out. Why is this the case?

 

[ArlyA]

A little off topic but train related. A few years ago we took Amtrak from Burlington Iowa to Denver Colorado. The train continued to California. The train was a 2 or 3 hours late on the way to Denver but was something like 10 hours late going home. The conductor sat down across the aisle from me and we talked for several minutes. He said the trains couldn’t go as fast through the mountains when it was hot out. Why is this the case?

That would be a new one on me. Does anyone have something smart to say about this?? The conductor may have been giving out good excuses.......

On a side bar, can anyone tell me why rails don't grossly expand and contract with temperature changes, length wise?

 

[RobS]

That would be a new one on me. Does anyone have something smart to say about this?? The conductor may have been giving out good excuses.......

On a side bar, can anyone tell me why rails don't grossly expand and contract with temperature changes, length wise?

The rails do expand and contract with temperature and I'm sure they have a means to deal with it in the track construction. Any one know how it's dealt with?

 

[Hay Dude]

A little off topic but train related. A few years ago we took Amtrak from Burlington Iowa to Denver Colorado. The train continued to California. The train was a 2 or 3 hours late on the way to Denver but was something like 10 hours late going home. The conductor sat down across the aisle from me and we talked for several minutes. He said the trains couldn’t go as fast through the mountains when it was hot out. Why is this the case?

This is a complete guess, so don’t laugh, but I wonder if its involved in the Diesel engines? mix high altitude with heat and it works a diesel harder. That may slow things down.
Or it could be typical Amtrak-always late :laughing:

 

[MossRoad]

Well, since you asked...

Expect Delays: Why Trains Slow Down When It's Hot

 

[ArlyA]

The rails do expand and contract with temperature and I'm sure they have a means to deal with it in the track construction. Any one know how it's dealt with?

This was a confusing point with me for many, many years, until I read this somewhere. The way steel is made has everything to do with this, that is almost all its expansion/contraction mostly goes one way, but hardily any on the other plane. With steel the molecules are round when them come out of the furnace but when its made into rolled steel, they get squished and that I mean, they are really flattened out. Just like wood, trees expand and contact with moisture largely by getting fatter/thinner boards, not longer in its lengthen (in the most part anyway). Steel does the same thing with heat/cold and in the case of rails, the vast majority of change is it the hieght of the rails, not there length.. Hows that? Of course the rail engineers still have some length changes to deal with, but its not very much.