FA2 vs FPA4

Can someone give me a quick rundown of the external differences between the FA2 and FPA4?

I'd like to have a model of a CN FPA4 and I'm wondering how much grief it would be to build one using the P2K FA2 as a starting point...

Steph

I can't really see a nickels worth of diff for a model between the two.

Here's nearly identical 3/4 views of each:

http://rides.webshots.com/photo/1034498 ... 5742Ygyksq

http://www.railpictures.net/viewphoto.p ... 48&nseq=12

Aaaaah...!

So it comes down to an extra couple of vents and a different fuel tank then. No dimensional differences I need to worry about?

Thanks for the pics, CarterB!

Steph

I don't know of any dimensional differences-- the extra vents below the radiator are the main spotting feature as far as I know-- but if you wanted to split the difference... as I recall, CN, in addition to its built-new FPA-4, had a small number of units (either 2 or 4) that had been rebuilt from FA-2 with 1800hp 251 engines. (I think they donated their old 244 engines for use in the weird little A1A-A1A roadswitchers used on PEI.)

Allen,

Thanks for that info - I'll keep looking to see what I turn up on CN-related 'sites.

I took some pics of the FPA4 at the Canadian Railway Museum when I was there a couple of years ago - that should get me started on the details...

Steph

Steph, I had a chance this afternoon after posting to check some books.

Kirkland's "The Locomotive Builders - Volume 2 (Alco)" says that the FPA4 (and also the FPB4 B-unit) was six inches longer than the FA2 (FB2). He DOESN'T say that the increase is in the carbody proper, and I would think that six inches COULD be the result of changes in coupler shank and mounting, BUT: (1) The 12-251 engine is a bit longer than the 12-244 and (2) the FPA4 has at least one more bit of internal equipment than the FA2 (see below), so it may be that the designers "stretched" the carbody to accommodate. (Maybe the exact angle of the diagonal truss members in the carbody structure isn't too important?)

Steinbrenner's "Alco - A Centennial History" confirms that four CN FA2 (well, technically, two FA2 and two FB2) were rebuilt with 12-251 engines (and the leftover 12-244 went into the RS24 units). He says, however, that the rebuilt units kept the FA2 configuration of air compressor aftercooler: a zig-zag of pipes mounted externally on the rear wall of the unit. They therefore would NOT have had the main FPA4 spotting feature: the extra vents velow the radiator intake shutters, which are for the compressor aftercooler.

So I'm not sure what to tell you. Good luck with modeling (and if anyone turns up more dimensional data, I'd be interested to hear it!).

Allan,

A 6" longer car body would be a bit of a pain! Things like that are rarely easy to sort out on a model. Just noticeable, but have I the patience...?

To be honest I'd always assumed that the FPA4 would be a bit longer, in the same way that the EMD FP7 is longer than a standard F7. It just wasn't obvious in any of the pics I'd seen or taken whether that was actually the truth.

Thanks for your help,

Steph

Steph,

The circular ring around the headlight lens is relatively flush with the grille, on the FA-2s, but it is raised slightly on the FPA-4s. This is more noticeable with some paint schemes (and lighting conditions), than with others.
http://www.railpictures.net/viewphoto.php?id=105841

http://www.rr-fallenflags.org/el/loco/erie7364alb.jpg

JR

jr,

Thanks for that - not something I'd noticed before, but now I can see clearly what you mean...

Steph

Note the lack of anticlimber on the FPA-4.

NY & Lake Erie has (had?) two ex-CNR FPAs-- one is the standard FPA-4, the other (6759, I think) is one of the "FPA-2s". The FPA-2 does not have the 244 in it. Don't know the current status of these two units; they may not have run for a while.

I had the opportunity to inspect the two NYLE units perhaps three years ago. At the time they were stored serviceable; IIRC they may have been used within the last year(?).

My notes are not handy, but I remember the FPA-4 being just as expected, 251 with static excitation, the front TM blower on the generator, with the rear one belt driven.

The other unit had the 251, Amplidyne excitation, and electric TM blowers, run off a second GY-27. It looks like all MLW did was take out the 244 and squeeze in a 251.

I believe the air was 24RL, and of course these units had roller bearings.

The NY&LE FPA's ran last year, I believe when that 0-6-0 tank engine was running down in Cherry Creek(?)

If you're looking for a model of an FPA4, why not start saving your pennies to purchase one of these:

http://www.divisionpoint.com/ALCO_FPs.html

ATK,

Loved the comment about the Division Point models! Maybe if I had more pennies and they were imported directly into the UK...!

All,

I'm now building up a reasonable amount of info on the differences. Thanks to EDM5970 for pointing out the anticlimber difference! The biggest problem now is finding out that the FPA4 is (as we suspected) 6" longer than an FPA2 or FA2. Any idea where the stretch is? In front or behind the radiator group?

The problem is that not only would a 6" stretch be visible in HO, I'd know about it in my model too.

Steph