What would be a typical F7 consist?

[tg626]

This isn't really TS2017 specific, or even TS specific as it could apply to an sim or even real world modeling, but I was wondering what would be a normal average consist for a freight headed by an F7 (or F7 A-B).

I know ruling gradient and weight are just 2 of many factors, but I'm looking for a real-ish starting point. For instance is a 30-35 car consist pulled by am F7A and F7B crazy short? Long? About right?

[buzz456]

Of course this varies a lot by grades but for starters you have three thousand HP on your described locos. As a kid on the old Milwaukee we used to see 50-60 cars regularly. I have no idea of course if they were full or empty so that's kind of a weak answer. The EJ&E that ran by my house was always about 50 cars pulled by a single 2000 HP center cab but it had to work it's a** off to maintain about 30mph on the just over 1 % grade going North hammer down.

[tg626]

Of course this varies a lot by grades but for starters you have three thousand HP on your described locos. As a kid on the old Milwaukee we used to see 50-60 cars regularly. I have no idea of course if they were full or empty so that's kind of a weak answer. The EJ&E that ran by my house was always about 50 cars pulled by a single 2000 HP center cab but it had to work it's a** off to maintain about 30mph on the just over 1 % grade going North hammer down.

Well that's a start anyway. I had 32 cars behind a F7A-B and was run 8 on Marias Pass up a 1.5% grade and running around 27MPH so that seems about right I guess. I'm just trying to get something that's reasonable as compared to prototype, so your real world report helps a lot!

[GreatNortherner]

tg626, this should be of interest to you:
http://www.mtnwestrail.com/aak/

It's a copy of Al Krug's Train Forces Calculator. Mr. Krug's website seems to have disappeared, sadly, but this little and very helpful tool seems to have survived at the Mountain West Rail website.

So for Marias Pass 1.8% ruling grade, a single F7 (1500 hp) could haul ten 80t cars up there at 15 mph but that would be an untypically short train for that line with very little local traffic and many long through trains. I remember seeing a fascinating black/white photo of GN's Western Fruit Express rounding the horseshoe curve at Blacktail, with four FT's in the lead, four in the middle, and four pushing in the back. The FT only had 1200 hp, but that would still allow for ~100 loaded cars.

On several railroads, F-units often operated in fixed lash-ups early in their lives, but later on they ended up being mixed matched with other locos as they became available. So for the example of Marias Pass again, an early GN diesel scenario would typically require "clean" ABBA or ABA sets of F-units, whereas in later years they would run together with whatever could be coupled to them, most commonly 1st and 2nd gen EMD hood units.

Cheers!
Michael

[ssbobz]

That's a shame about Al's site. I think I printed out his examples of calculating the physics a while back for reference, I'll have to see if I can find it.

[_o_OOOO_oo-Kanawha]

Thoese early cab unit Diesels replaced steam and essentially pulled the same trains.
Steam usually had the horsepower/cost advantage over early Diesels once past medium speed, but by starting tractive effort Diesels beat steam locos by a margin. Lash ups of small HP Diesels were needed to get the same medium speed horsepower of modern steam locomotives.
Well up into the sixties with the advance of second generation Diesels and more 100 ton cars train weight grew significantly and operating practices changed accordingly.

[BoostedFridge]

That's a shame about Al's site. I think I printed out his examples of calculating the physics a while back for reference, I'll have to see if I can find it.

Not to derail TG's post, but some of Al Krug's site still works: http://krugtales.50megs.com/rrpictale/rrpictale.htm

[GreatNortherner]

Thank you for the link, BoostedFridge! Now if you'll excuse me, I'll be downloading the Rules articles from Al's website.