Posts Tagged ‘Figure’

how do you figure out a diesel-electric’s tractive effort?

Sunday, November 4th, 2012

Question by DixieLiner: how do you figure out a diesel-electric’s tractive effort?
I am building a model railroad with a ruling grade of 3 – 3.5%. Time is early fall 1979 (or late winter 1981). My roster consists of 3 GP9s outfitted with 567D3A prime movers rated 2500hp. 2 Alco PAs and 3 PBs outfitted with 1800hp 251 prime movers, and 3 to 10 SD35s. My trains will consist of 2-12 cars + caboose. I would like to run up to 45 car trains. Most traffic will consist of lumber/forestry products, automotive, and rock from the 3 online quarries.

I found an army site with some equasions
HPx30= starting Tractive Effort : HPx300/speed=TE

and No of Cars = TE/ [3+(20xruling Grade%)]xWeight of cars

Also included was tables for weight of car taking into accout friction and drag like a 70Ton car would be 105 in the equation and a 120T would be 160 Tons.

Does this sound right? or do I need to find a table somewhere with similar grades and use their TE tables or what? Thanks in advance for any help provided.

Best answer:

Answer by HOGHEAD
Rolling train resistence formula:

HPT x 12 / %G = S, or, horsepower per ton times 12 divided by the per cent of grade equals speed. Drag is figured into the equation and does not need a separate operation to arrive at.

I worked the Siskiyou Branch of SP’s old Oregon Division. Ruling grade was 3.1 per cent. Drawbar tonnage was 2700 tons max. Units were SD-40’s and 45’s and were rated for 900 tons per unit.

But, rule of thumb in real world railroading, about 25% of the locomotives weight is what will be developed for tractive effort. So, a loco that tips the scales at 400,000 lbs will develop at least 100,000 f/lbs torque. In actuality, an average 40 or 45 puts out 105,000 f/lbs. tractive effort.

I never met a GP-9 with 2500 hp. All I ever ran were 1800 hp. So, at 1800 hp each, your three Jeeps would handle around 1350 tons max, on your 3% grade. Your Alco’s would then handle 2250 tons on a 3% grade.

I’m running 70 car trains on my little outfit with needed helper power. I have found that if the power is split according to real world entrainment formuli for helpers, with the helper pulling 2/3s and shoving 1/3 of the total helper tonnage, the helper won’t push any cars ahead off the track.

You sound like a purist, but, weren’t the Alco PAs long scrapped before ’79? They tried using some newer obsolete Alcos (can’t remember the model) as yard engines in Roseville in the mid 70’s, but the rigid trucks, designed for main line rail, just wouldn’t stay on the rails in the yard. If you looked at them cross-eyed they’d fall off the track…..

But, they were nice on the road, rode well, and with the 16 notch throttle the power could be regulated better.

I think I have operators manuals for these critters around here some where. Drop me a line and I’ll try to get some more dope for ya………

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how to figure disending grade?

Sunday, October 28th, 2012

Question by deadmans hand: how to figure disending grade?
I am building a grade on a model railroad and am trying to stay between 1.5 & 2.0 percent on the grade . It will fall a total of 4.5 inches in roughly 25 feet . I dont think it can be done in that short a distance with out it being over 6 + percent ,any help appreciated .

Best answer:

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O Scale Layout Figure 8 under the Hellgate Bridge

Thursday, September 27th, 2012

Here’s a little video montage running the figure 8 under the Hellgate bridge on my layout. Lionel’s O scale New York Central RS-11 pulling a mix of Lionel & MTH freight. Tried doing some different viewpoints than before. Hope you all enjoy the ride. Thanks as always for viewing and hope everyone is well. Please be kind and rate & comment. Subscriptions always welcome too !!!
Video Rating: 4 / 5

Mountain lion figure for model train?

Monday, December 5th, 2011

Question by lemonsandlimes: Mountain lion figure for model train?
I have a friend that is working on a model railroad set. I want to get him a mountain lion (cougar) figure. Where can I order one?

Best answer:

Answer by Old Man Dirt
Go to the Walthers site (http://www.walthers.com/) and find the one for his scale. You might have to buy a set of animals (like for a circus or zoo). But if there is one in his scale, more then likely Walthers will have it. Then find a local dealer to go through to order it. There are some one line places like caboose hobbies (http://www.caboosehobbies.com/catalog/index_brief.php) that can also order it for you and ship by mail.

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DARLENE – MOTORHEAD MINIATURES 1/24 SCALE MODEL FIGURE 237

Wednesday, October 12th, 2011

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trying to figure out how to connect control switch for a lionel santa fe twin diesel electric train set?

Wednesday, October 5th, 2011

Question by aglee: trying to figure out how to connect control switch for a lionel santa fe twin diesel electric train set?
model no.6-1285 trainmaster safety transformer no.4250 027 gauge

Best answer:

Answer by yarnlady_needsyarn
Contact your supplier, or check our Lionel online.

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MERMAID – PREISER HO SCALE MODEL TRAIN FIGURE 29012

Thursday, August 18th, 2011

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HO Scale Figure 8 Train Track Accessory Set by Hawthorne Village

Friday, July 15th, 2011

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MERMAID – PREISER HO SCALE MODEL TRAIN FIGURE 29012

Tuesday, June 21st, 2011

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HOMELESS MAN ON BENCH – PREISER HO SCALE MODEL TRAIN FIGURE 29094

Monday, May 23rd, 2011

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