Engine "Slippery-ness"

[NW Mailing List]

I should have mentioned that one of the best examples of an A's performance right on the edge of its max capability is on Winston Link's Mainline to Panther album/CD.

There is one sequence where an A is westbound on Blue Ridge grade and manages to keep moving with an overload down to about 10-12 mph. It holds the rail for a considerable length of time, with the two engines going in an out of step, sometimes staying one way or the other for sustained periods of time. It finally slipped, reportedly on the turnout near the summit and was unable to recover.  Generally when one engine of a 4-cylinder simple slips, the throttle must be shut off all the way until the slip stops.  In the cited example there was one slip with full recovery, and two additional slips in succession before finally stalling.  It's great example of a very skilled crew getting every last ounce of low speed performance from an A.

BTW, the A's FA is 3.79 based on its RATED TE, which at low speeds is less than what the locomotive actually developed during tests. 

Dave Stephenson