What would be considered the maximum number of cars for an Athearn Sd 40-2 r-t-r engine be able to pull without problems? ( I understand about weight of cars etc. etc. Just an average)
MAXIMUM NO. OF CARS?
EASY. Tell me the truck’s friction coeffictients, and weight of each car ,VS car the weight of the engine and ‘slipperyness’ of the wheels on your track, and grade - if any - and I’ll make an educated guess.
Real Railroads compute tonnage vs weight of the engines, with their combined horsepower, and the terrain being covered. One engine to 12 cars is not uncommon. Most HO engine’s will pull 15 cars on a level test track…
Heavy model engines will pull more cars but need bigger motors to do so. Bigger motors raise the cost to modelers like you. Most factories try to compromise.
Want a real ‘puller’? My champion is the Proto 2000 SD-60. Paint jobs dont seem to make much difference. Brands do (see compromise). .
According to a MR product review, the P2K SD-60 will pull 93 cars. The Athearn SD40-2 will pull 69 cars. They (MR) measure the drawbar pull in ounces and convert that number to an equivalent amount of cars. That eliminates grades, curves and track conditions from the equation. Here is a link to some MR reviews, you will need to go through the list and find the diesels so you can compare them.
http://www.trains.com/Content/Dynamic/Articles/000/000/004/329dqilq.asp
Jim
Everyone has their ideas on what the maximum # of cars a locomotive can pull.
I have my own.
I add cars to a locomotive until it stalls on one of the two 3.5% grades on curves I have.
My IHC 4-6-2 is limited to 5 Athearn Heavyweight passenger cars while my Athearn BB SD40-2 barely slows down with 30 cars.
This is how I find out the maximum # of cars a locomotive will haul on my mainline.
I find the Athearn RTR SD40-2 not as heavy as my BB’s so I doubt it will haul as much as my BB’s but I haven’t tested it yet.
Gordon
next time i walk into the LHS im going to walk out with a SD60! [:D]
Jim, the MR review is for the B-B not the RTR. B-B uses sintered metal wheels which provide excellent traction but get dirty easier. RTR uses brass (I think) wheels that don’t provide as much traction but have better elec contact.
here’s how Jim Hedger (senior editor of MR ) does this
i’ll post how to calculate drawbar pull of model trains later.
I didn’t know anyone still made locomotives with brass wheels. All of the higher end locomotives I’ve seen, including Athearn RTRs were nickel-silver. Just my [2c]
In our experience it’s the old reliable Athearn Blue Box Superweight F7 for pulling power …yes along with the P2K SD60 which is also very impressive on our grades.
Mine would pull 42 to 50 with no problem. More than that and I got derailment troubles, so that was the limit rather than pulling power of the lokey.
And Nickel Silver is a type of brass.
Fred
dingoix;
I know that review was for the BB, which, as you pointed out have the iron wheels. Most, if not all manufactures today are using N/S wheels. I could not find a review for the RTR SD40-2 but here is one for the Athearn RTR SD45T-2.
http://www.trains.com/Content/Dynamic/Articles/000/000/006/070skgwi.asp
MR also rates this loco at 69 cars but it may be heavier than the RTR SD40-2.
Jim
The RTR SD40-2 most likely only has enough power to pull maybe 35-40 cars. The RTR SD45T-2 has gigantic weights in it, giving it the 69 car traction.[:D]
I just bought a RTR Athearn F7A-B and was wondering how many cars they would pull??My layout is a shelf layout with very little grade.I was planning on pulling about 20-30 40foot box cars and a caboose,it should do that,shouldnt it??
tim, I highly doubt it. I’m pretty sure a 4 axle Athearn only pulls 20 cars & I’m assuming your B unit is a dummy. If your B unit was powered you could pull 30 cars just fine.