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Between Denver and Colorado Springs, the mile-long coal trains climb a steep hill near Larkspur. Modern AC locomotives provide their maximum tractive effort at walking speeds, and that's how fast they go.

What is the gradient at Larkspur?

I would agree that for high speeds on freight routes, lower gradients would be in place. I would even agree that speeding up trains would increase costs. However, the speed-power curve of electric locomotives allows definitely more than walking speeds. Some maximum gradients on European corridors with substantial freight traffic:

  • Øresund Link: 1.56%, passed with 90 km/h I believe;
  • Lötschberg line: 2.7%, Gotthard line: 2.8% (2.6% on most of the climb), passed at 75-80 km/h


*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Sun Dec 14th, 2008 at 01:56:25 PM EST
[ Parent ]
But also a larger share of bulk freight in Europe is water freight, so much of that freight on those lines might fall within the design envelope of what is called Rapid Freight Rail in this diary (and for US contexts elsewhere).

The appropriate consist for high speed container freight on a schedule and the appropriate consist for coal or marble being delivered at lowest cost per ton-mile on the basis of getting there before existing stockpiles exhaust and not wanting to tie up the cars for an excessive length of time ... are two quite different things

It is straightforward that a medium freight train can go up a hill faster than a heavy freight train, especially if that is both a shorter consist and less weight per axle, provided that the commercial advantage of the speed justifies the higher power per ton required.

Adding capacity for a different class of freight changes the commercially preferable speed in that capacity in the same right of way, which changes the optimal super-elevation for that new capacity for that different class of freight, which reduces the time required to traverse bottlenecks on the route, which increases the proportional benefit of higher speeds elsewhere in the route.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

by BruceMcF (agila61 at netscape dot net) on Sun Dec 14th, 2008 at 03:26:44 PM EST
[ Parent ]
What is the gradient at Larkspur?

I found this in a rail forum:

Rocky Mountain High - RailroadForums.Com

The track in this area climbs through an undulating 1.5% grade through Tomah and Larkspur. Trains are moving anywhere from 10-15 m.p.h.


*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Sun Dec 14th, 2008 at 05:07:32 PM EST
[ Parent ]
HA! Even better:

Crawling Coal on the Joint!

Also gone are the days of speedy ascents up the hill between Denver and Palmer Lake, at least for BNSF. In the 70's, coal trains typically had 21,000 horses to climb the 1.2% to 1.5% grade. With SD60's in the 80's, that increased to 21,200 horses. Today, however, you find those four 4,000 horsepower SD70's totalling 16,000 horses, a full 5,000 short of what you would find 15 years ago! With the advent of AC technology, coal trains can crawl along without stalling.


*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Sun Dec 14th, 2008 at 05:10:54 PM EST
[ Parent ]
... between heavy bulk freight and anything else:
From what I've been told in Denver, its a money issue. BNSF went to the customers and said "hey, we can move your coal cheaper, BUT its going to take a few hours longer to get there." The customers and BNSF benefit from not adding additional power to the train. Essentially they bring the engines down to their knees for 20 miles or so but in their eyes they save money.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.
by BruceMcF (agila61 at netscape dot net) on Sun Dec 14th, 2008 at 09:31:22 PM EST
[ Parent ]

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