6 axle athearn sd-40-2 keeps on derailing

M

mikebalcos

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Aug 9, 2006
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Quezon City, the Philippines
balcos.blogsite.org
i have an athearn sd40-2, but the front axle keeps on derailing at 18" curves. :( my guess is that my tracks are a little misshaped already (and that because i do not nail my tracks on my layout; i want the layout to be still modifiable since it is still pretty simple). are 18" curves the minimum for my 6 axle sd40-2? my 4 axles do not have a problem.

oh btw, just to confess, my other 4 axles include 2 F7As and an athearn rdc. so i was preferring 1960 era engines. but my dad got me this sd40-2, and i'm not strict on the eras. i would love to see this sd40-2 running along the track. :)
 
Have you tried running the SD40 with the B end forward to see if it does the same thing? (The B end is the end opposite the cab). If the same thing happens, it may be the track. If not it could be wheel spacing on your front truck. Do you hace a wheel gauge?
 
I too have an Athearn SD40-2, Chicago & Northwestern #6935. It absolutely LOATHES 18" curves. When it goes into a curve it makes a loud grinding noise that sounds as if the mechanism is binding up, which goes away once the track straightens out again. In fact, out of my six locomotives with 3-axle trucks (C-C or A1A-A1A) only my Athearn Fairbanks-Morse H24-66 Trainmaster seems to have no difficulty with 18" curves.

I wasn't a member during the "Diesel of the Week" thread featuring these locomotives, so I'll post its picture here. It is unfortunately permanently relegated to the roundhouse until such time as the layout is expanded and the curves eased.

Dsc00205.jpg
 
cidchase said:
If the trucks rotate enough to acommodate the turn, what about removing the flange from the center wheels?
I know some steamers (models) are built this way because of the wheelbase. I think it
would hardly be noticeable on a six axle diesel.
Click to expand...

The SD40 can go aroud a 18" curve

Another thing to check out is wether your Trackwork is as good as it can be

I'll close by saying that on my layout, whch had bad trackwork, my SW1500, Athearn wouldnt even get out of the spur, yet my (well it was on loan from a club) SD40-2 almost made it around the whole layout

Alexander
 
I have four Athearn blue-box SD40-2s... Had them since 1988. I don't run them much though, because I don't have much room and am restricted to using 18" curves. I found that having a bit of bank (superelevation) on the curves do help keep them on the tracks. They do stay on the rails with the bank, but the pilot overhang do tend to exert a lot of lateral force through the couplers and can derail cars being pulled by the engines.

For that reason my 4-axle Geep fleet is far larger-- 22 of them, all Athearn BB's. :D
 
LongIslandTom said:
I have four Athearn blue-box SD40-2s... Had them since 1988. I don't run them much though, because I don't have much room and am restricted to using 18" curves. I found that having a bit of bank (superelevation) on the curves do help keep them on the tracks. They do stay on the rails with the bank, but the pilot overhang do tend to exert a lot of lateral force through the couplers and can derail cars being pulled by the engines.

For that reason my 4-axle Geep fleet is far larger-- 22 of them, all Athearn BB's. :D
Click to expand...

Yeah, its pretty much accepted that if your going to run 6 axle motive power, it will have overhang and ont look pretty

BTW, if you really want big power, the Atlas SD24 handles 18" easily, it doesnt look that bad on them
 
Long wheel base 6 axle units and 18" curves are not the best combination.Best to use larger curves for these types of 6 axle units.You see that SD40-2 is a scale 68 ft 10 in.On the other hand a SD24 is 60 foot 8 inches and that scale 8 foot 2 inches can make a difference in the size of curves these units will take.
 
brakie said:
Long wheel base 6 axle units and 18" curves are not the best combination.Best to use larger curves for these types of 6 axle units.You see that SD40-2 is a scale 68 ft 10 in.On the other hand a SD24 is 60 foot 8 inches and that scale 8 foot 2 inches can make a difference in the size of curves these units will take.
Click to expand...

Yes, your right there, ths SD40-2 is longer than my SD24, but the SD24 Looks like a big unit, compared to a GP7.

It seems that the more modern time periods have longer locos, while pre 1980 is a lot shorter, save for the E Units, etc
 
alexander said:
Yes, your right there, ths SD40-2 is longer than my SD24, but the SD24 Looks like a big unit, compared to a GP7.

It seems that the more modern time periods have longer locos, while pre 1980 is a lot shorter, save for the E Units, etc
Click to expand...

And just think you can hide that SD24 behind a 60 foot boxcar! sign1 And that SD24 was a long unit in its day.Btw..You can hide a E8 behind a 73 foot center beam..:eek:
 
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