Coupler tensile load ?

[bruce22]

Can anyone tell me what this load might be on the trailing coupler of say a six unit diesel with a 100 car train at start up.

[maxman]

bruce22

Can anyone tell me what this load might be on the trailing coupler of say a six unit diesel with a 100 car train at start up.

 

Starting uphill, downhill, or on the flat?

 

If you google tensile force on a railroad coupler, you'll get a lot of information, including this: http://answers.yahoo.com/question/index?qid=20100101103332AAjP45e

[gmpullman]

You can start here:

http://en.wikipedia.org/wiki/Tractive_force

then here...

Granted, these figures are for steam locomotives but for that first coupler on that 100 car train drawbar pull is just the same. It relates to the tractive effort of the locomotive. You can look up the rated tractive effort of the particular locomotive you have in mind and apply these formulas to them.

Train handling comes into play here as well. A heavy-handed throttle jockey might break a knuckle or pull out the drawbar and a more experienced engineer will know how to use his slack and load meter to get the train moving without breaking it in two.

Here's a good discussion covering tractive effort and drawbar pull.

http://www.railway-technical.com/st-vs-de.shtml

Hope this helps, Ed

[bruce22]

Thank you Gents, I will try the sources mentioned.

[Eric97123]

Here is info for a more modern drawbarhttp://www.alkrug.vcn.com/rrfacts/drawbar.htm

[jrbernier]

  Al Krug's site has lots of real good information.  Off the top of my head I was guessing 330,000-360,000 lbs - I see he is quoting 390,000 lbs from the air brake rules book.

  One of the issues with running up mountain grades is the strain on the couplers/drawbars.  A while back folks were talking about putting the old Milw Snoqualmie Pass line back in operation or send more WB traffic over Stampede Pass - The reality is that it would take three sections of the same loaded unit train to get over Stampede - Not going to happen financially!

Jim

[West Coast S]

SP operating practices prohibited double heading AC class engines in freight service as the combined starting tractive effort could and did destroy couplers and draft gear, double heading on passenger operations was permitted due to the substanial nature of couplers and draft gears unique to passenger equiptment and the lower overall tonnages involved.

Dave