No, it’s not Northwest -vs- Southwest. Visually, what is the difference between an NW2 and an SW7? I know that the NW made 1000hp and the SW made 1200hp. They both look the same to me.
Thanks.
On the front of the body of these locomotives, there’s a screened intake for the radiator. It’s big and you can’t miss it. On the SW7, the bottom of this intake is down near the deck. On the NW2, it stops way short. The intake for the NW2 is about 5/8 as tall as the one on the SW7.
Ed
Thanks. I’ll look again…
Oh yeah, I see it now. I was always looking at just their sides.
Also, the cab front windows on the NW are older, arched type.
Except when they’re not. Consider NW2 BN 569. Square cab windows and SW7 style louvers, BUT with the NW2 shorty radiator. Photo on page 106 of the 1974-75 BN Annual.
Ed
The NW-2 went thru I think five different ‘phases’ or changes over the years. The last NW-2’s in the late forties were very similar to the first SW-7’s. If you look at the first NW-2’s from the thirties, it’s easier to see differences.
Another difference, not readily apparent, was the fact that the NW’s had welded frames built up of steel plates, while the improved steels after the war made possible the cast frames of the SW’s. They were denser and heavier, and allowed higher horsepower, with its higher stresses. jc5729
BN 546-573 were originally CB&Q 9200AB-9213AB and were built as TR2 cow-calf sets. The calves were later fitted with cabs by CB&Q but were not re-numbered and by that time the square cab windows were standard.
Also, cast frames are found only on some Winton-engined switchers, models SC and NC to be specific. Everything with a 567 engine has a welded underframe.
John Colley wrote: “the NW’s had welded frames built up of steel plates, while the improved steels after the war made possible the cast frames of the SW’s. They were denser and heavier, and allowed higher horsepower, with its higher stresses.”
Not so John. In EMC/EMD’s prewar nomenclature, there were two switcher models, with either 600- or 900-hp Winton 201-series diesels, and each was availalble with either a cast or a welded frame. Six-hundered-horse switchers were either SC (cast) or SW (welded) models, and the 900-horse switchers were either NCs or NWs. When the NW was given a 1,000-hp 567-series engine it became model NW2 of 1939, which continued in production until 1949. The NW2 was succeeded by the 1200-hp SW7 beginning in October 1949, by which time EMD had decided to drop the horsepower-based nomenclature and use “SW” as the model designation for all switchers.
But like the NW2 that preceded it, the SW7 was built on a welded frame, which was always Electro-Motive’s preferred approach. Presumably the cast frames had been offered to assuage the fears of master mechanics who’d grown up with steam and “knew” that cast frames were better. Even today’s monster six-axle diesels are built on welded frames.
(Other remnants of the horsepower nomenclature lasted longer. The first E units were rated at 1800 hp, and streamlined passenger units remained “Es” even as their horsepower increased. The first freighters had 1350 hp, which EMC rounded up to 1400, and were thus model “FT.” But of course the “T” was later dropped so “F” could simply mean “freight.”)
So long,
Andy
Another spotting feature for most of the NW-2 switchers was the step in the hood, just in front of the cab.
This one was built from an Athearn (mislabelled) SW-1500, following an article in Model Railroader. Besides the obvious changes, the 53 has pick-up shoes, a GSB cab interior, and a large Sagami can motor, and has been re-geared with Ernst gearsets.
Wayne
Yes I forgot about that, on the NW (or at least the early ones) there was a flat area in front of the cab windows before it tapered up to the roofline on the long nose, like on your model. On later GM switchers, the taper started right at the windows, right??
BTW very nice switcher Wayne!! Reminds me of the CN engine that worked on the DW&P in Virginia MN for many years. [:)]
Thanks for the kind words, Stix. The paint scheme was loosely based on CN’s, and I used SMP’s Accupaint CNR Green and Yellow on my free-lanced conversion.
Wayne