Question on F2, F3, F7s on B&M

[SSW9389]

Note the first three B&M F7As have sequential EMD Serial Numbers, and the first three were on consecutive EMD order numbers. Mr. Kristopans who created the linked website used EMD records for his data.

http://community-1.webtv.net/ajkristopa ... page3.html

8476-8477 03/49 (E1173)
Boston & Maine 4266-4267

8478 03/49 (E1174)
Boston & Maine 4265

9932 10/49 (89930 sold on 6059)
demo 930 to Boston & Maine 4268

12303-12304 07/50 (6138)
Boston & Maine 4265B-4266B

12382-12383 11/50 (6150)
Boston & Maine 4267B-4268B

Ed Cooper
who writes for Wikipedia as SSW9389

[SSW921]

EMD F7A 930 was built as a high altitude test unit for the Engineering Department in March 1949.

[b&m 1566]

I just recently learned about that, if I recall it was tested on the Rio Grande, then after a couple of months, it was sent back to EMD. From there it was painted up to match the CBQ livery and sent to Chicago Railroad Fair of 1949. When that was done 930 was returned to EMD and purchased by the B&M in October(?) of 49. It was cleaned up, re-engined, re-numbered and painted into the B&M livery.

[SSW921]

I haven't seen any source saying it was reengined. The 1959 EMD Product Data shows a 16-567B block with a serial number that dates to March 1949.

[CSRR573]

If you look at the pilots of 4266 and 4265 compared to 4266, you'll notice the pilots are different too

[bmcdr]

What differences are you talking about? Both the 4265 and 66 were identical, when 4266 was re-habbed and painted in the so-called 'Blue Dip" in August 1969, there was a lot of body damage including a rotted out number indicator, missing stainless grille section on the Engineers side, and missing removable panel below the front coupler. A replacement number indicator was poorly welded on, the missing grille was replaced with "chicken wire" and the front removable panel was replaced with a solid piece of steel that was welded across the bottom of the pilot. That is the only difference......solid bottom as opposed to having a removable panel, other than that modification, the 4265 - 4267 were identical.

[arthur d.]

Probably a typo where it was meant to suggest comparing the pilots of 4265, 4266, and 4268

[b&m 1566]

I haven't seen any source saying it was reengined. The 1959 EMD Product Data shows a 16-567B block with a serial number that dates to March 1949.

Of course I can't find it now, I've tried looking. I suppose its possible I'm getting my info twisted, it certainly wouldn't be the first and I'm willing to bank on that being the case this time.

[urrengr2003]

Last year at North Conway observed an F-unit with the left side front porthole set back approximatel 1/2 the width of the porthole with that of the right side port hole. Have worked on hundreds of F-units in 42 yeras of engine service and never noticed this on other units. My recollection is that both front porthole windows were centered exactly where the main resevoir discharge pipe went vertical up into the engine room ceiling on its way to the intercooler. On the outside looking looking thru the windows, the discharge pipe was centered in the opposite side window. The B&M unit at North Conway had the left window located to the rear of the unit far enough that it did not backlight the main resevoir discharge pipe. Is this unusual or is it a B&M standard?

[Engineer Spike]

It is true. There is a site with the builder numbers of all of the early EMD products, and also references the order numbers. 4268 was a separate order number, and its builder number was not consecutive with the rest of the class. It seems to be fairly common knowledge amongst B&M fans that 4268 was a demo. It also has a different style pilot than the rest.

[Manalishi]

I was just browsing the internet and came across Wikipedia with some information about EMD - F7’s and noticed something different about the B&M F7 roster. Who ever put the page together states that B&M 4268 was originally EMD demonstrator 930, can anyone confirm this? Until now I was under the impression all F7's were purchased new in 1949 along with the F7b’s a year later.

What a coincidence, I googled 'EMD F7' today and got the same wiki page! Anyway I got the impression that the B&M only bought 4 of those F7A locomotives (4265-4268) but I've seen pictures of other F7s on the B&M mainline. For example, 3812 and 3808. So, is it known just how many F7As the B&M actually bought?

I've also heard them referred to as E7s. What's the difference?

[chrisf]

The E7 is a completely different model of locomotive. It’s a 6 axle, 2 diesel passenger locomotive, while the F series has only a single Diesel engine and 4 axles.
https://en.wikipedia.org/wiki/EMD_E7
https://en.wikipedia.org/wiki/EMD_F7

[b&m 1566]

Manalishi - The B&M had 70 total engines that had the similar looking "bulldog" nose look to them.
24 FT's, 18 F2's, 2 F3's, 4 F7's, 21 E7's & 1 E8.

[Manalishi]

Thanks guys. I've got 2 photos in my collection of what I thought were F7 locomotives (3812 and 3808) passing through Newton NH but it turns out they were E7s. As B&M 1566 points out they both have a similar look to them.

The E7 was more powerful but is described as a passenger locomotive. Since it's more powerful than the F7 wouldn't it be used to pull a freight train? After all, wouldn't a freight train be heavier?

[arthur d.]

An E-7 certainly has more horsepower, but its not that simple. It's all about tractive effort, weight on drivers, and gearing. While an E-7 has 6 axles, it still only has 4 traction motors, like an F unit. That center axle on each truck isn't powered, Hence the A1A -A1A wheel arrangement designation. (vs a B-B designation on a F (or GP) unit) Weight gets spread around more, reducing weight on driven axles, makes for a smoother ride, but less tractive effort. And gear ratio's are lower for a freight engine, makes it easier to start a heavy train, but doesn't produce the speed of a passenger engine. (It doesn't have to). As you already know, a passenger train is lighter, and needs to get over the road faster, so a passenger engine has higher gears, but can still get a passenger train moving without much trouble.