double heading

Model Railroader General Discussion (Model Railroader)
1

How many 40’ coal hoppers can I pull (realistically) before I should run two loco’s, SD40-2’s.

Thanks Ken.

2

From your signature, I thought you’d be asking about double headed steam. Hmmm.

Who makes the SD40-2? Do you have any grades? Many sharp curves? Empty hoppers?
On flat land, I say 35 loaded hoppers before straining.

3

Aggrojones

BLI makes the loco’s, 2.5% grades, 20ish" turns, HO, empty and full hoppers.

I kinda meant prototypically how many before they would MU?

Ken,

4

Aggrojones was right to ask because the prototype would be taking that all into account. They try to run exactly the amount of power they need. Otherwise it’s a waste of money for them. You might be able to answer your own question by going to www.railpictures.net and looking up a unit coal train pulled by SD40-2’s and counting the cars. Personally I’m interested in the nuber as well.

Jesse

5

for modeling purposes with selective compression I’d say any more than 15 cars and I double up, at least that’s the rule I use.

~METRO

6

I’ve been running 10-12 cars and one loco, I’m just starting on the coal mine yard, and wanted to put a loco run around track, so I may need room for two loco’s.

Ken.

7

weight of train and power says how many engines to use plus any grades.
Use the same concept for the model.

Or just doulble up anyways to make sure…

If a train couldnt make it up the hill, they would double up the train, take half the train up, come back for the rest.

oh the fun of operating…

8

Keep in mind a lot of the prototypes use multiple locos whether they need them or not for the pulling power, just so that a unit failure doesn’t disrupt traffic flow on the system. CSX has one old two loco lash up around here I don’t think they ever seperate, even on 9 car trains.

9

Too may variables (Multiple answer’s).
Weight of engine = weight of cars…
PLUS
truck friction (rolling)
empties vs ‘loads’

You basically add cars until the wheels slip.
Want to pull more cars? - Use freer rolling trucks.

10

Thanks everybody, I’ll make my run around track big enough for aleast two loco’s

Ken.