Steam & Excursion > The DeVoy Trailing Truck

Thank you Martin and Marty for the great series of pictures of Milwaukee steam power!

Most of these pics show engines which feature the DeVoy trailing truck under the firebox.  I have two articles written by Bill Wilkerson from which I'll pass along highlights concerning the DeVoy truck.

J. E. DeVoy was the Milwaukee's Chief Mechanical Officer and designer of almost all of their locomotives for the construction of the Pacific extension during 1907 to 1914.  The DeVoy design trailing truck was a feature on 195 K-1 class 2-6-2's, 20 L-1 2-8-2;s, 180 L-2 2-8-2's, 70 F-3 4-6-2's, 25 F-4 4-6-2's, 70 F-5 4-6-2's, 23 N-1 2-6-6-2's, 16 N-2 2-6-6-2's, 9 A-2, 4-4-2,s, 17 A-2a 4-4-2's, and 17 A-2b 4-4-2's.  It seemed to work well for him.  One engine, a K-1, was converted with a Delta trailing truck as an experiment - which was never repeated.

It was the first successful design of a movable trailing truck. 

Early 4-4-2 Atlantic types had a trailing truck under the firebox that had no lateral movement (sometimes called the "Northwestern Type"),  For the longer wheelbase of his K-1 2-6-2's DeVoy felt he needed more lateral movement, so he designed his inside bearing trucks with rollers and concave ramps to assist in stabilizing and centering.  It was also marketed to other railroads by the Standard Car Truck Co. and was used quite a bit nationwide until the development of outside bearing designs.

These trucks lasted on the Milwaukee (and likely elsewhere) into the '50's.

-Larry Doyle

 



Edited 1 time(s). Last edit at 12/07/18 15:52 by LarryDoyle.

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Thanks for the information on the inboard bearing trailing truck on the 2-6-6-2 in Martin's post from yesterday!   

The secret seems to be the call-out #6:  ‘spring plank and rollers”.
[ in between nos. 7 & 5, in the sketch]
i was trying to figure out what allowed the axle to be a movable ‘truck’...

i suspect that the roller pockets, in the upper bar use a more complex top curve, than the sketch suggests*.
Are there any extant engines with the DeVoy truck, as examples?   Are there any currently operating?

Also item 4, a 15” wear plate, is a generous design...and makes lots of sense, along with taking a battering...

​W.


*. There’s an interesting little sketch, shaped like a brassiere, at the top of the drawing, that seems to give clues as to the ‘roller curves’, top & bottom.  
Is the date ‘1884’  accurate, or is the sketch from the later century ?



Edited 3 time(s). Last edit at 12/08/18 04:06 by wcamp1472.

Cast iron brassier????

Anyway, here's a better scan, slightly enlarged, of the roller arrangement Wes refers to, 

The date on the drawing is 5-5-84, the date Bill Wilkerson put on it, so that would be 1984.

-John



Edited 1 time(s). Last edit at 12/08/18 09:27 by LarryDoyle.

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  I find that early technology is quite surprising with there constant new ideas. Unlike today when computers do the work which took months to do back then.  There were many unknowns back then also with no previous experience to pull from.  Many worked fine and hardly changed over the years. Boyd in Chiloquin.

I wonder how the performance of this truck compared to the Rushton Trailing truck, which was common at this time.  It relied on swing links for centering.