PRR T 1 Modified

[uncljoe]

Try to figure out what the term "Modified" on PRR T 1, 5500 loco means ?

Semper Fi
 Joe

[altohorn25]

Try to figure out what the term "Modified" on PRR T 1, 5500 loco means ?

Semper Fi
 Joe

It means that most of the original skirting has been cut away to help the shop gangs with maintenance work.  I don't have photos that I can upload right now, but there were three different versions of the skirting:  first version had portholes on the sides of the pilot and deep skirts that covered the top half of the drivers, second version still had the portholes in the pilot but the running board skirting was raised to expose the drivers, third version removed the portholes from the sides of the pilots in order to get at more of the front end stuff. 

This of course does not include the two prototype engines; they were different as well.

In addition to the skirting changes, the paint job on the loco changed each time they removed skirting. 

Also, they moved the Keystone number plate from down on the pilot to up on the smokebox cover somewhere in there as well.

The Broadway Limited model is the engine in it's final configuration.

Nate

[uncljoe]

Thank you

[chicken45]

I remember some discussion, possibly in a book, suggesting that T1 had changed enough to actually be reclassified as a T1a, but that never happened.

[mmagliaro]

There was a single T1 fitted with more conventional Walschaerts valve gear in the late 1940s, and that single engine was designated a T1a. The rest of the T1 engines had poppet valves because supposedly the poppet system's ability to separately control the intake and exhaust points made it more efficient, especially at high speeds (and the T1 was designed right from the get-go to be a high-speed engine)

[chicken45]

There was a single T1 fitted with more conventional Walschaerts valve gear in the late 1940s, and that single engine was designated a T1a. The rest of the T1 engines had poppet valves because supposedly the poppet system's ability to separately control the intake and exhaust points made it more efficient, especially at high speeds (and the T1 was designed right from the get-go to be a high-speed engine)

Thanks, Max!
That sounds like what I was referring to.

[peteski]

There was a single T1 fitted with more conventional Walschaerts valve gear in the late 1940s, and that single engine was designated a T1a. The rest of the T1 engines had poppet valves because supposedly the poppet system's ability to separately control the intake and exhaust points made it more efficient, especially at high speeds (and the T1 was designed right from the get-go to be a high-speed engine)

That answers my question of why I kept seeing T1 photos on the Internet with 2 different valve gears.   Thanks!

[mmagliaro]

"Pennsy Steam A to T" by Paul D. Carleton, and its companion volume, "Pennsy Steam, A Second Look", are the best references I have ever found on PRR steam (at least as far as hard-bound books). I know the first book has a section on the T1 that discusses the T1a valve gear.

Oddly enough, this discussion made me realize that I have been missing the "second look" book for years and have no idea what happened to it! Since a used copy was on Amazon for only $16, I ordered it. 

How about that? I bought a PRR book for the first time in at least 10 years. (Just because I live in NP country now doesn't mean I am not still interested in the PRR).

[peteski]

How about that? I bought a PRR book for the first time in at least 10 years. (Just because I live in NP country now doesn't mean I am not still interested in the PRR).

I'm not surprised. Once PRR gets in your blood, it stays with you for a lifetime. 

[chicken45]

LOL to bring this full circle...back in 2009 when I was getting back in to trains, Max actually recommended that book to me (which I promptly bought!).