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I’m not familiar with these locos - could you explain the reference to “articulated frame”?

Jack can probably answer this better.  There was a whole bunch of experimental stuff built into the A-1, and the T&P 600s came right after that.  I’ve heard several reasons why, but the main frame ends at the back driver.  The firebox is supported over top of the trailing truck and the drawbar attaches directly to the back of the trailing truck.  It’s a bit of a Frankenstein design that caused no shortage of problems and Lima moved away from it quickly.  A few of the 600s were upgraded to a new full frame, delta trailing truck and roller bearings towards the end, but none were saved.  It improved the engine but not enough to starve off dieselization.

@kgdjpubs posted:

Jack can probably answer this better.  There was a whole bunch of experimental stuff built into the A-1, and the T&P 600s came right after that.  I’ve heard several reasons why, but the main frame ends at the back driver.  The firebox is supported over top of the trailing truck and the drawbar attaches directly to the back of the trailing truck.  It’s a bit of a Frankenstein design that caused no shortage of problems and Lima moved away from it quickly.  A few of the 600s were upgraded to a new full frame, delta trailing truck and roller bearings towards the end, but none were saved.  It improved the engine but not enough to starve off dieselization.

My understanding was that the trouble with the articulated trailer was that they tended to derail when backing up with any appreciable load in back of the tender. Apparently they were fine when pulling in a forward direction.

Fortunately, backing movements tended to happen during low speed switching. I don't recall reading about any major catastrophic wrecks being caused by the articulated trailing trucks.

 

My understanding was that the trouble with the articulated trailer was that they tended to derail when backing up with any appreciable load in back of the tender. Apparently they were fine when pulling in a forward direction.

Fortunately, backing movements tended to happen during low speed switching. I don't recall reading about any major catastrophic wrecks being caused by the articulated trailing trucks.

 

there were also some excess stresses on the firebox with the design, if memory serves 

Last edited by kgdjpubs

The circular ones were more accurate than the trusty linear K&E's many of us carried. One of my high school teachers had us make two linear logarithmic scales on two different sheets of paper. Putting them together created the basic slide rule scale. I once took a college physics final after a night of partying and luckily had a small pocket slide rule that came in handy for the problems. Made a B+!

I have a collection of fairly accurate models -  thinking about Hot's comments about center of mass, I can see his point for all but low speed switching locomotives.  When getting to the center of mass becomes a long stretch, as with 4-10-2s and 4-12-2s,  the crosshead is guided further behind the cylinder to reduce main rod length.

A quick glance at my display shows the main driver almost always somewhere close to the middle of the boiler.  Only not true for 0-4-0s and Harriman 0-6-0s.

it is harder to see on articulateds - in the case of the Challenger, it is probably driven more by main rod max angle, and interchange of parts between engines.

C&O's class J-1 4-8-2 (the first "Mountain" type built) had 61" drivers and the main rod connected to the third driver.  After years of counter balance problems C&O went and extended the cross head guides to a second yoke, lengthened the piston rod, and shortened the main rod to reduce the problem (I don't know how successful it was).

Stuart

Hello all,

First time I ever posted, so please forgive my rookie flubs and if there is a better place to post this. Not sure if this is of interest at all: Based on this thread, i purchased a copy of The Steam Locomotive in America by AW Bruce. Great book! The book came from South Carolina.

Upon opening the book, out falls a faded newspaper clipping (scan attached). Its from the Charleston News and Courier dated Jan 20 1964. It says:

"Number 32 moves up North. Number 32, a 68 ton Baldwin 10 wheeler from South Carolina's 17 mile Hampton and Branchville Railroad, is being repaired by the York Southern group which has been running excursions - temporarily diesel powered - on the 38 mile Maryland & Pennsylvania Railroad.  Officials hope Number 32 will make a shakedown trip out of York PA sometime this winter"

I would just like to add what a great group you all are, generous with your knowledge.  Thanks to and inspired  by you all, i hauled out my original Lionel, started tuning it up and got my Grandson hooked.

 

 

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