BIG Disappointment !!!!!!!!!!

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Maxitrains

Member
Finally I got my long waiting ( from US ) Athearn SD40-2 loco BNSF, and my eyes sparkled. To my disappointment, I went to try it on my layout and it won't go on most of my curves :(. This means 3 things, either I have to start changing all my curves again, sadly sell the loco :( or put it on the shelf just to watch it.

Any other ideas?

I really like this loco :)
 

Selector

Well-Known Member
That bites!!! I don't mean to talk down to you, but are you absolutely certain the matter is between the trucks and the curve radius? What radius are we talking about, and what does the literature say about the minimum for this engine? Is it possible that you have a dip somewhere at a joint on a curve that causes one of the outer flanges, or even a wheel on the inner curve, to leave the rails? Have you removed both trucks to see if they can turn freely through the arcs designed by the manufacturer? There may be something preventing a full pivot, such as flashing or some piping that is bent. Is the coupler pin at the right curvature and height...not snagging on a tie or a frog? They'll even snag on a guard rail...honestly!
 

Larry

Long Winded Old Fart
I have a pc. of plexiglass the same size as an engine w/a long wheel base.
I mounted a pair of trucks w/3 axles. You can put stops on the bottom of the plexiglass to be the same as your engine turning radius. That way you can check the engines radius limits. Almost all my large Athearn engines take a minimum of a 24" to 26" radius.
You can also take a piece of flex track(preferably 3ft section) & find out what radius the engine needs by bending the track to different radius.
Then U will know what is really needed to make "it stay on track(pun inteneded)".
The newer engines in all mfg'er's seem to need a larger radius because of all the details they are adding under the loco's. I had to do some trimming on a set of coupler pockets to make an engine that I have turn on a 24" radius & the manufacturer stated it needed a 26" or larger radius. Don't do that till you try all other avenues of trials.
My 2 cents worth.

Larry
 

Maxitrains

Member
Well, as for this engine, I tried it quickly on the layout to see how it runs, so I haven't even instaled anything on it, not even couplers, so I ran it all by itself, but this is a much longer engine from the others I have, so mostly the layout was tested on the others.

As for dips & gaps, actually the rails are not yet fixed, so it could be it as well, but only this engine so far does this problem.

For the radiuses I have to check exactly what I placed, I forgot all the curves, but some of them has mixed radius rails to fit and join, I know its wrong, so I think I have to get some flexi tracks and replace all the curves. Some curves I mixed like two different types or radiuses and some other places I even fitted curved straight ( or whatever its called ) a sort of half curve half straight, normally used after a switch to get straight parallel to the main line.

I will check again all the rails and see what I can change from it.

I also don't know how much the "trucks" can turn on an engine like this.

Thanks for your replies
 

RCH

Been Nothin' Since Frisco
Athearn's SD40-2 should operate on curves as tight as 18" radius. Any tighter than that and you'll have problems.
 

Maxitrains

Member
I went to try the loco again on some curves, and on some it was jumping off, from a joint, even though the joint was well fitted. But I could see that the trucks were somehowstressed on these turns. I will check all curves and see if they can be changed to wide ones, the only curve I tried and did not derail, was a 431mm Radius.

Is there any way how the trucks can be made to turn a little more? A few millimeters could do the trick.

Thanks!!


BTW I have some curves that are 360mm Radius ( about 14½" ? ), I think that's small.
 
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ThoroughBreed

Dcc~detail~diesel freak
On the Athearn units, if you take the trucks off the frame and file down the inside of the frame some, it will turn a little better, but beware, the more you take off, the more likely the worm gear and driveshaft will bind.:cool:
 

jbaakko

Diesel Detail Freak
I discussed this with Maxitrains on MSN messenger. I suggested, if he wanted to keep it, to see about filing a bit off the insides of the truck holes, to allow it to turn better.

The drive shafts can be an issue, but are savable, by doing a dual knuckle, though you'll have to trim the shaft shorter, it might work, with a little blocking to keep it from pushing to far to the sides and opening up...
 

Larry

Long Winded Old Fart
The last 2 Athearn engines I bought would not turn on 1 of my radius tracks.
I did a lot of testing w/my plexiglass trial car & found that the wheels were pressing against the coupler pockets. I cut away some of those & it turned another 1/8th of an inch which helped it to turn on a smaller radius. I'm not saying this about your engine because I haven't seen 1 lately. I have had problems in the past w/engines jumping off curves because the trucks were hitting something. You can remove the shell & see a lot more than U can w/the shell on. Try running it w/out the shell before you file off anything.

Larry:rolleyes:
 

wongsing

Member
Could you post a pic of your layout in question...It could be helpful for us in suggesting solutions. I (personally) would not go to the level of internal modifications until the expense of alternate solutions out weighs the cost. I have 2 Athearn SD40's and one SD38 and my layout is only 4'x8'...Some of the Atlas and Bachmann switches I have would not allow my locos to go through without derailments, so I pretty much scrapped the layout and invested money into going to a model railroad club...Being over in Malta, you may not have that option :( ) On the other hand though, you may want to consider some larger radius turns. It should be fairly affordable, and not only will it preseve the original good running characteristics of this loco, but any other of your 6 axle locos will be better off as well! BTW: How many 6 axel engines do you have? I had the same problem with my 6 axel locos, but NEVER with my 4 axle locos. So, in the end, my suggestion is to lay some slightly larger trackwork (I'm no seasoned professional, but I am starting to realize that you will have to re-lay your track constantly until you get it just right!) and keep the loco you wanted so badly. This way, nothing gets filed, sanded, or potentially broken (*not trying to talk down to you either by no means, but modifying a locomotive chassis can be quite complicated...And pretty risky unless you have been modelling for a decent amount of time*) and you have a layout that much more fun to run. This is just my personal opinion though... Could you also maybe post a decent pic of that BNSF SD40...they're some of my favorites!

-Rich

-Rich
 

Maxitrains

Member
Larry, I will try to take your advice and take off the cover and watch what is happening closer.

Rich, this is my first 6 axle truck loco ( and I love it :) ), and with 4 axle locos I never had suck problems accept lately with a new RS-3 loco which was pushing the bogie of the car attached to her out of the rails in these same places where this 3 axle is pushing a wheel out.

and here's a picture of the SD40-2 I have PICTURE I still donno how to place a thumbnail :p

I mostly noted that the derailment occures on these mid point of tight turns especially when the wheels meet a joint, even it its very smoothly joined. Maybe if I take out all the curves and try to place a whole track ( flexi-track ) it could help alot, and also shape it in the way it needs.

Any suggestion on how to curve a flexi-rack in a uniform curve??

The followng is my layout and its plan

Layout_2_sm.jpg

Plan_1_exsm.jpg


I will try to take another shot of my layout from a slightly elevated position, so the curves can be seen better.

The following pics show the problem I am having with the RS-3 at some point.
RS-3_turn_2.jpg

RS-3_turn_1.jpg
 
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B_Kosanda

Member
The struggles you are talking about here have caused me to stop buying Athearn locomotives. Too many derailments for me. Curves have been trouble as well as picking points on many switches. To me it just was not worth all the pain to get the locos to run right. Now they sit in the yard and look pretty. I have turned to Kato and Atlas now.

Bill
 

Maxitrains

Member
Ok, maybe this loco (SD40-2) is big for my curves, but are you saying that you bought the same model but of a different brand ( Atlas / Kato ) and they worked, or you started buying smaller locos from Atlas and Kato?

So if I should buy an SD40-2 from Atlas, you sayig it will work on my same curves?


Or am I understanding all wrong?
 

ThoroughBreed

Dcc~detail~diesel freak
Part of the problem your having with that rs unit is that the couplers are body mounted on the engine, but truck mounted on the car. You have a fixed pivot point on the engine and a movable pivot point on the car. Do you have any cars with the couplers mounted to the body of the car instead of the trucks? If you'll use those cars closer to the engine, you'll see a definite improvement. Also do you have access to Kadee couplers? Definitely invest in them as they have a wider pivot than the horn-hooks that come with cars/engines, and look alot better. If you decide to go to Kadee couplers, it won't be hard to convert the cars with truck-mounted couplers to body-mounted.
As for the derailing SD40-2, check your trackwork over real carefully. Look for slight imperfections, small humps in the roadbed, become more prevailling in the track. Check for level across rails, along with along ties.:cool:
 

Maxitrains

Member
I cannot understand how a car with a fixed coupler to the body can improve the turn on the curve without derailing. the problem of deraiing the car is because the coupler on the loco is on the back end where on the curves it goes out of the tracks, and by so it pushes the car out.

As for new couplers I'm already waiting for a whole lot of them, bought them about a week ago and now waiting for them to arrive. I hope they work better.

And for the SD40-2 derailing I'm planning of buying some flexi-tracks and change all the curves with them ( remove curve pieces and place one whole piece of flexi-track ) which will have no joints and avoid most of the derailments.


GEEEE! I'm thinking, I'm almost re-building all the layout track allover again.

Well track laying, ain't that hard, mostly is the base that has to be more accurate and needs alot of work.
 

kjd

Go make something!
It looks to me like the curves are very sharp. The angle between the RS3 and 40' car is very sharp for shorter equipment. It will only be worse with longer equipment like an SD40-2. It is even a prototypical problem. The 2nd sub on the old Camas Prairie was limited to 4 axle locos and 75' cars and I am sure there are lots of other examples. I have about 60 or so BB Athearn locos, 4 Katos, 4 Atlas and 2 P2K and they all work great on my curves but they are much bigger than the ones above.
As far as smooth curves with flextrack, I made a template from stiff paper. I laid out a stick with the radii marked on it. I drilled a hole for a pencil and a nail in the other end. I cut them out and used them to lay out the curves on the plywood. As I laid the track I ran my fingers along the curves to feel any irregularities. A few got redone but eventually I was pleased. I used Atlas Code 100 on my last layout and slid the rail half out of each piece so the joints were staggered 18 inches on a 36 inch piece of track. I don't know if that would work well with other brands.
 

B_Kosanda

Member
Ok, maybe this loco (SD40-2) is big for my curves, but are you saying that you bought the same model but of a different brand ( Atlas / Kato ) and they worked, or you started buying smaller locos from Atlas and Kato?

So if I should buy an SD40-2 from Atlas, you sayig it will work on my same curves?


Or am I understanding all wrong?
I run all 6 axle locos and I'm saying the Athearn 6 axle locos are prone to derailing. In my experience the Kato and Atlas 6 axle locos are very much less likely to derail. I believe the Athearn units are very suceptible to any irregularity in the track, where other brands seem to be more forgiving.

Bill
 

Maxitrains

Member
Thanks, its something to keep in mind for future locos. Still I'll be checking and changing some tracks from my layout, its better to have a single rail without any joints in a curve, where its more prone to have derailments.
 

Steve B

Firefighter
My SD40-2's, at least a couple of them had wheelsets out of gauge,,, I.E. they were to far apart on the axle, they climbed off at any opertunity given to them, re setting the wheel's on the axle to the correct distance fixed this, you can get a gauge to measure this. As for derailing trucks on curves, body mounted couplers on your freight cars will help, truck mounted couplers gave me headaches just like that, i cut em all off and screwed KD number fives direct onto the underside of the body at the correct height, i also binned all those horn hook couplers
 




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