# Dd40



## bradimous1 (Mar 3, 2010)

this will not run on 18" curves correct?

ATHEARN DD40 DIESEL ENGINE - SOUTHERN PACIFIC SP #9503


----------



## sstlaure (Oct 12, 2010)

I don't think it would. That's a seriously big engine. (It's like back to back GP40's in length. Very cool engine, but really long. The U50 is another giant engine that wouldn't like tight curves. (although it's possible that the trucks may swivel enough that it would work....sometimes you never know.) 

I think the 8 wheel trucks would be the biggest problem. Are any of the center wheels flangeless? Some companies go blind flange on the inner wheels to allow them to negotiate tighter curves.


----------



## bradimous1 (Mar 3, 2010)

sstlaure said:


> Are any of the center wheels flangeless? Some companies go blind flange on the inner wheels to allow them to negotiate tighter curves.


I was asking because I was looking at one on ebay... and as of right now, I only have 18"... don't think it is worth the risk at this point... I'll put it on my bucket list one the new layout is up and running.


----------



## Artieiii (Apr 25, 2011)

I like those giants. Symbols of american ingenuity. Kind of like the UP turbines the Big Boys etc.... I would like to add one to my fleet sometime in the future. For some reason I like the Athearn DD40 the best but the price is keeping me away plus I hate to spend the money and find out it won't run on my tracks.
-Art


----------



## sstlaure (Oct 12, 2010)

I wish I modelled UP because they've got all the cool HUGE equipment. I also like the turbines, big-boys, centennials, Uboats, etc. I bet those things (even the models) pulled an incredible load. I just recently saw the U50's, I like those as well because they are a diesel, but they look like the old cab-forward 4-8-8-4's with their flat noses.

I would think they'd need at least a 22" if not a 24" radius.


----------



## deboardfam (Oct 8, 2010)

http://cs.trains.com/TRCCS/forums/p/123530/1402004.aspx

Some cool pics of a 15" radius curve and several models there including a DD40


----------



## NIMT (Jan 6, 2011)

Surprisingly it will handle 18" radius curves, It overhangs a lot! Keep good track side clearance! If you pull too much weight in a tight curve they will pull the cars right off the track with no problem!





























































With these 4 DD40's that are twin motored, 4 flywheeled, 7 skewed pole motored, DCC matched, monsters, I have pulled over 150 cars, that was all the room i had on my main line at the time! I think they could pull even more!
Word of caution if your going to DCC them you need to pick a strong DCC decoder, I use NEC D13SR with no overload problems!


----------



## bradimous1 (Mar 3, 2010)

thanks guys... I have DC, so not an issue at this point. I am eying one on ebay... current bids are only at $43 and change.


----------



## gc53dfgc (Apr 13, 2010)

I have bought the new Athearn U50 (pics tomorrow) and I can confirm it will handle 22 radius and should easily handle 18 as the trucks are two sets of two axle trucks for the front and the same in the back. Both of the pairs of trucks turn so it is able to move much more freely then a DD40 could and Sean showed that they do work on 18.


----------



## sstlaure (Oct 12, 2010)

That's awesome.


----------



## Massey (Apr 16, 2011)

A word of caution on the Genesis models, while the engine may handle the 18" radii that does not mean the first car behind the engine will too. I had a Genesis SD70MAC that would take the 18s on my layout just fine but it would throw the car behind it off the rails. Truck mounted couplers may have helped prevent this but none of my equipment have those. If you open up the coupler box's sides to allow more deflection this will solve that problem. 

Massey


----------



## gc53dfgc (Apr 13, 2010)

That will not be a problem with the Veranda turbines or the U50s as they have truck mounted coupler boxs not body mounted which will allow for greater movement over the body mounted type.


----------



## tkruger (Jan 18, 2009)

The original Athearn DD-40s have the truck mounted couplers. I have three of these. The best solution I have found to knocking the cars behind off the track is to us a car less than 50 foot or one with talgo trucks behind the loco. Also if the first car is a little on the heavy side it helps allot. These are beast when it comes to pulling. Added flywheels to mine to help smooth them out. 

If the front truck tends to derail in an 18r turn then replacing the power bar with a piece of wire may fix the issue. On one of mine the bar was hitting when the truck turned and not allowing it to fully turn to the right. Also replacing the bar with a soldered wire increases the connectivity.


----------



## NIMT (Jan 6, 2011)

Yes the top power feed bar on the Athearn BB units is a "must" to replace!
Before I converted my fleet to DCC, I changed all the bars out for wiring and it made a huge difference in there performance!


----------

