High Plains Rail Operation

[Big Cat]

Last Fall, my wife took a trip from the upper Ohio River Valley to north central Montana and back. Several interests were explored along the way to keep everyone happy, but generally we were following Lewis and Clark.

 

We stopped at the Rochelle, IL rail park.  The webcam does a good job showing stuff, but everything seems closer when you're there.  The gift shop has many interesting items.  We also stopped in Hill City, SD and experienced an enjoyable ride on the Black Hills Central Railroad.

 

After exploring the territory and reading several Trains articles about the High Plains, I had several questions.

 

1. Steam Locomotive Performance.  There was an ongoing blog about measuring performance of steam engines which was very informative.  However, from science class and cooking instructions, water boils at a lower temperature at high altitudes.  Does this affect the operation of the locomotive?  If it does, how is it dealt with practically?

 

2. Diesel Locomotive Performance.  I know that they have turbochargers.  What is their function?  Are they regulated to keep Sea Level Pressure in the intake? Are they unregulated and just operate off the exhaust? How much do they help at the higher altitudes?

 

3. Train Air Brake Performance.  Does it take significantly longer to charge a train in the mountains vs the lowlands?  Does the higher altitude have effects on the braking system? Will a train bleed off sooner?

 

Thanks.

[tree68]

Big Cat

2. Diesel Locomotive Performance.  I know that they have turbochargers.  What is their function?  Are they regulated to keep Sea Level Pressure in the intake? Are they unregulated and just operate off the exhaust? How much do they help at the higher altitudes?

I'm not an expert on Diesel technology, and I slept in my recliner last night, but...

I believe turbos just run off the exhaust - there is no regulation.  I normally note about 7-10 PSI of "boost" in notch 8.  You'll have to dig into basic Diesel theory as to exactly what a turbocharger does.  

You might also find the Roots Blower used on early EMDs interesting.

As for brakes, there's nothing in our rules that I can recall addressing altitude.  

[MidlandMike]

Water boiling in a teapot is an open system, open to local air pressure, which is lower at altitude.  In a water system, lower pressure allows a lower boiling point.  A steam engine is more of a closed system where internal boiler pressure is more controlled, and more isolated from outside pressure.  Not sure if the reduced partial pressure of oxygen would affect coal burning.

[timz]

Big Cat

How much do [turbochargers] help at the higher altitudes?

Probably the web has a few EMD service manuals for 1970s models. As I recall a GP38-2 would lose maybe 7% at 6000-ft altitude while a GP40-2 was around 3%.