DanG
New Member
Posts: 8
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Post by DanG on Jul 11, 2018 22:08:40 GMT -5
I'm looking for a high level rule of thumb here. I know we could get deep into the weeds with this (what rolling stock, what are the rates of incline on the layout…) and if someone want to go there that's fine. High level 1 loco per x-number of cars being pulled. Please forgive me if my terminology is not correct, I'm just getting started in the hobby and feel free to correct me.
Thanks,
DanG
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Post by markm on Jul 11, 2018 22:39:44 GMT -5
Dan, Welcome to the forum and welcome to the hobby. Your question is a bit vague. If you are thinking about what the prototypes do, I'd suggest a rule of thumb of a locomotive for every 10-20 freight cars and one for every 5-10 passenger cars. From the standpoint of the capability of most AZL locomotives you can easily double those numbers. I'd suggest you look at some of the railroad image sites such as: www.rrpicturearchives.net/default.aspxfor details for specific roads, locations and eras. Hope this helps, Mark |
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Post by bnsantaray on Jul 14, 2018 20:03:53 GMT -5
Dan there is no absolute rule.....
I remember as a station opr seeing each saturday the Quebec-Montreal Rapido passenger with 4 engines and 4 cars....so it is up to you
Ray former CN opr-dispatcher
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Post by ProgressRail on Jul 15, 2018 8:27:09 GMT -5
Power Bureau & Operations Management do not make locomotive ID-assignment decisions based on "x" amount of freight cars in a consist; in-short basic form for the purposes of this forum, power is assigned to trains based on several different factors including horsepower-to-tonnage ratios, territory grade, loads vs empties, special_handling instructions, # of powered axles, etc.. Saying "you have this many freight cars so you need this many unit's" is very far from how the real world operates; and looking at image sites does nothing but give you exactly that, a reference picture to look at for detail, not operating conditions & parameters.
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Post by markm on Jul 15, 2018 8:34:36 GMT -5
Ray I agree that there are literally 1000s of exceptions to my rule of thumb, that's why it's important to check out the real trains, either images or the prototypes, to get a feel for what's being done.
To add a couple more examples, around Stockton CA, BNSF runs a 4 unit SD70 consist. Some days it's pulling a 100 car train, other days 4. In the same area, UP runs trains with 2-3 units up front and one de-powered unit on the end, apparently as a control cab.
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Post by dazed on Jun 18, 2021 22:01:40 GMT -5
To add a couple more examples, around Stockton CA, BNSF runs a 4 unit SD70 consist. Some days it's pulling a 100 car train, other days 4. In the same area, UP runs trains with 2-3 units up front and one de-powered unit on the end, apparently as a control cab. I wonder why UP is shutting down the DPU. I've never heard of that. Are you sure they are shut off? |
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Post by markm on Jun 18, 2021 23:12:06 GMT -5
Perhaps de-powered is a poor term to use. When the DPU passes, one can look right through the equipment bay to other side of the track, no visible power equipment. It really appears to act more like a caboose. These trains are mix merchandise and pass through Lodi and Sacramento where a number of posted videos were recorded. Have a look and give me your opinion.
Another additional thought for the thread: SP on the Overland route east out of Roseville did what seems unique in the early 60s. They would lead with an F7 ABB set, followed by an AB set 1/3 along and another AB set 2/3, followed up by three cabooses. I count 100 cars per train and it always seemed to me that they had merged three trains together.
Mark
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Post by dazed on Jun 19, 2021 12:17:19 GMT -5
Ah, ok. What you're probably seeing is an SD70ACe (and possibly a few other models, but the ACe's are particularly noticeable) that has a pretty "see-thru" intake. (similar to the old "Tunnel Motor" SD40T-2/SD45T-2) They're still very much powered as a DPU.
BN commonly ran five 6-axle units (SD40-2's and C30-7's) on coal trains. (110-cars at that point I think) The SD70MAC's came along and three replaced the previous five....sort of. I do think they lost some headroom, and when they went to 120 cars it resulted in reinstituting helpers in some areas. Then they went to DPU and that sort of went away, then they went to 132 cars...helpers back. Then 2008 recession happened and all of a sudden plenty of locos...been running 2+2 ever since.
I think the OP is asking about models, and I would probably disagree that Z-scale locos outpace the prototype. Maybe on flat/modular layouts and/or 100% ideal conditions, but introduce a 2% grade, curves, track imperfections, slinky couplers, dragging wheelsets, etc and I'd say the pendulum swings the other way. Fortunately, from a practical standpoint it's probably never going to be much of an issue. Most people are never going to run a 100 car train on a 2% grade as home layouts can rarely handle trains of that length, and show/modular layouts--where 100 car trains ARE more typical--are usually flat.
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Post by husafreak on Jun 19, 2021 20:26:30 GMT -5
At the end of the day tonnage and drag determines how many engines are required, but logistics probably really decides, as long as the minimums are met extra engines going places to do other stuff is what's really happening.
At the airlines your best chance of an empty flight is the really early or late ones, which are often being repositioned for the next day, passengers is just a bonus!
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Post by neverland on Jun 26, 2021 20:45:13 GMT -5
Dan, welcome to the forum. Great inputs from everyone but in the end it’s your railroad side run your consists just the way you want it!
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