I recently saw an article on the T1 Trust Facebook page I had never read. It was quite interesting. It had lots of stats and comparisons of the PRR T1 and the N&W J as well as others.

It was a very interesting read from the 2012 Classic Trains mag. A PDF of the article is below. Check it out if you have a few extra minutes.

No big surprise, the N&W J was superior up to 70mph in most categories, but above that the T1 dominated.

An excellent read.
Thanks.

Thanks for posting this link. I hope more people will read the article and comment on it (good or bad!!).

Jeff,

You are correct, the article was not intended as a direct comparison of the T1 with anything else. It was a very condensed history of the locomotive, with the goal of putting it into perspective as evenhandedly as possible.

The comparisons are important to show what the railroads needed, not to make a "I'm bigger than you" thing.

The drivers split than being a 4-8-4 is the effort to reduce side rod weight and rail pounding and achieve better balance. Again the T1 ran on a more level route than the J which had to pound the mountain grades.

Whatever the complexities needed to run the T!, perhaps today's computers can simplify the demands, give note to the T1 trust in their efforts.
perhaps the ACE idea has merit here.

I found it interesting that the divided drive concept was initially proposed by Baldwin, as a method to reduce dynamic augment and improve counterbalance at high speeds. I seem to recall that of all the major builders, Baldwin had the least advanced engineering for calculating counter weighting; some sources simply say their formulas were incorrect. It seems other builders were able to do a better job of balancing conventional 4-8-4's for high speed operation, leaving the divided drive as a solution in search of a problem.

If one wants some detailed comparisons, the N&WHS had a very detailed writeup on the J vs. T1 tests on the N&W. Very worthwhile reading if this kind of thing is of interest to you.
Kevin

There is an upcoming article in the next PRR T&HS "Keystone" comparing the T1 to another locomotive numbered 611. This one, a bit smaller than the N&W variety.

But just as significant, albeit for different reasons...

It wasn't so much that Baldwin's engineering methods were the least advanced. Baldwin precisely followed the AAR recommendations for balancing; it's just that the AAR recommendations caused problems. Two notable Baldwin designs that ran into problems were the New Haven 4-6-4's and the Atlantic Coast Line 4-8-4's. Some other roads like the UP ignored the AAR recommendations, used less reciprocating balance on contemporary designs, and had no balancing problems. Judging from the construction of the ACL 4-8-4's, an exacerbating factor may have been the apparent extra-heavy construction of the reciprocating components like the pistons and crossheads.

At any rate, it seems pretty obvious that the balancing problems did drive Baldwin to come up with the duplex drive.

Another advantage claimed for the duplex, was the reduction of pressure loss in the cylinders (valve chest, passages). Since each cylinder only had approx. half the steam flow of a two cylinder engine at similar horsepower output.

Tom Hamilton