coefficient of friction 1

[proejuan]

What is the coefficient of friction for calculate the pull force in a rail car?

 

[civilperson]

Steel on steel ranges from: High of 0.78 to Low of 0.05. Use of sand box required on slippery surfaces such as leaves, oil, & ice. Use 0.25 for design purposes, (2% maximum grade).

 

[wiktor]

Typically 0.005 i.e 5 lbs per 1000 lbs.You can find more details here:

https://atiam.train.army.mil/soldie...w/public/7489-1/fm/4-01.41/chap10.htm#tab10-1

 

[harrisj]

At a mu of .005, a 100-ton locomotive will achieve a drawbar pull of 1000 lbf. That's not much of a train.
The loco won't even make it up a 0.5% grade on its own, let alone pull anything else up it.
Something wrong here. Civilperson's numbers look more realistic, although I've never come across as high as 0.78 before.

 

[civilperson]

Two different questions have been answered in the above postings. The rolling resistance of a towed rail car is given as an average by witkor, the tractive effort as a drawbar pull by a locomotive is given by civilperson and harrisj. The Army Manual cited by witkor has both answers. The STE, (starting tractive effort), is given as 0.3 to 0.2 with .25 as a design value and the CTE,(continuous tractive effort), is half of the STE.