Damn you N scalers!

Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here)

#21
Well, today wasn't as exciting as I'd hoped. I tried gluing down the JTT grass mat. It's paper backing. It wrinkles and shrinks. It sucks for long runs. ended up pulling up the 24" square at the end. Should have stuck to my gut and plastered the foam then painted and used turf instead.

Then, I figured I'd hook together some track and just tack it down so I could see the train on this table. I know I will need one loop so I staggered the sliding rail and then soldered three sections together while pinned to a straight edge. Put the loop down at an 11" radius. Loco derails as it begins the turn. No matter how I manipulate the loop, derail at the beginning. Kato even states 11" radius for flat and 15" radius for viaduct track. I had to stop as the frustration was getting the best of me.

Any suggestions on the track issue? I cut out an 22" circle and used that to give me my track bend. Hell, I'm even bringing the inner ties against the template which means 11.5" at track center. I tried pushing it out to 12" and it still derails.
 

wombat457

Well-Known Member
Staff member
#22
Olie,

Does the engine derail at a join? If not, check the spacing of the rails where the engine comes of. If it (the spacing between the rails) is correct then try another engine and see if it derails in the same spot. If another engine navigates the same section of track without an issue, check the trucks and wheels on the engine that derails. One of the trucks could be catching and not turning as it is suppose to. If another engine derails in the same spot, check to see that the track is laying flat and hasn't lifted on one side or even buckled.

Also, what engine is it that is derailing? I have numerous Kato engines, F7's and ES44Ac's where the recommended min radius is 12" but they navigate my wife's 9" curves pretty well with the exception of a little binding.
 
#23
Tony,

Unfortunately, I only have one N scale engine. The engine is the FEF-3. All 9 rolling stock cars go around fine, just the engine. At first I thought the tender was hitting the back of the loco, pushing the front wheels off the track. Nope. I moved the loop section so it's not at a junction, still hops the track. I don't have a track gauge for N scale but I'm gonna pull out the calipers and see if that's it. 8.93mm to the inside edge of rails. Only other thing I can think of is when I did the decoder, which was fairly extensive, I messed something up with the wheels or trucks. Here's some pics just as it starts to hop the track.
 

Attachments

wombat457

Well-Known Member
Staff member
#24
The second picture shows the leading wheels on the engine off of the rails. The only reason I can think of for that is the radius is too tight for the engine to keep all 8 main wheels on the rails.

Someone else might have a better explanation but I can't see anything obviously wrong with the track work that might be causing the derailment. Sorry mate, wish I could be more help.

Only other thing I can suggest is to borrow another engine and see how it runs.
 

tootnkumin

Active Member
Staff member
#25
Looking at picture 2 (drivers/front truck), what is noticable is that the front wheels of the lead truck are still on the track. If it was the tuck derailing, I would expect those wheels to have come of first, ditto if it was a track blemish causing it. To my eyes it looks to be too small of a radius for the driver's overall wheelbase to negotiate. The front driver has ridden up onto the outer rail and is lifting the truck's rear wheels with it. It's the drivers that are derailing and pulling the truck off, not the other way round.
 
#26
Looking at picture 2 (drivers/front truck), what is noticable is that the front wheels of the lead truck are still on the track. If it was the tuck derailing, I would expect those wheels to have come of first, ditto if it was a track blemish causing it. To my eyes it looks to be too small of a radius for the driver's overall wheelbase to negotiate. The front driver has ridden up onto the outer rail and is lifting the truck's rear wheels with it. It's the drivers that are derailing and pulling the truck off, not the other way round.
I understand what you're saying but the radius is over 11". I've been searching around and it seems some have had similar issues due to the front wheels are too fine for code 80 track. Several people replaced the wheel sets and the problem was solved. As this is my first Kato loco, I don't have anything to compare it with.
 

tootnkumin

Active Member
Staff member
#27
What model makers usually do to help long wheelbase locos get around small radius's, is either have the center drivers with no flanges, or allow a fair bit of sideways movement of each axle to allow for the misaligning that the track's curve is forcing on them. Being that they are all connected with the driving rods, the 2nd option can be compromised.
 

wombat457

Well-Known Member
Staff member
#28
Olie,

If others have had similar issues due to the front engine wheels then perhaps there lies the issue. What I don't understand with the reasoning is if the front wheel can jump the rails on Code 80, then they'd have buckleys chance in hell of staying on the rails with Code 55.

It might be the reason but I can't understand the logic or reasoning for it, it just doesn't make sense to me. I really don't think it has anything to do with the front wheels because they are still on the rails in the second picture. The only wheels that are off the rails are the leading two main wheels that can't turn. Regardless of what Kato states, your FEF has too many main wheels for the radius you have.

One way to prove or refute that is to increase the radius of your curve. Make a long straight section and make a 14" radius curve at the end, it doesn't have to be a full curve. Run the engine around it and see what happens. If it makes it without an issue, reduce the radius to 13" and run the train again. If it makes that radius without an issue reduce the radius to 12" and so on until it derails again.

I'll bet my bottom dollar (almost) that it will run on 12.5" radius curves and beautifully on 14". That doesn't help you at the end of the day because you are restricted to 11" radius, BUT at least you will have identified the problem OR eliminated one of the possible problems.
 
#29
Here's the latest update. One of the front wheels was wobbling on the axle. I adjusted as best I could but without a gauge, it's hard to tell if it's set correctly. Ordered one tonight. Second and most importantly, I think my wiring coming from the engine body to the tender is messing with the drawbar. I thinks it holding the loco from turning as far as it can. Ordered smaller wiring as well, we will see.

The part that still gets me is the 4 drive wheels won't make the turn even at approx. 14" radius. Mind blowing. So, I'm setting this project aside until the supplies come in . I start vacation this weekend so I have next week to mess with it. Need a break.
 

bob

Administrator
Staff member
#30
That's prototypical. Here's what happened when we tried to take a 4-8-4 around a sharp curve in Tacoma. Rolled the rail right over!

070608_steam_locomoti_2ED90[1]_thumb.jpg
 

new guy

Active Member
#31
An understanding spouse is a key to this if you are married! I got lucky she NEVER comes down to the mancave! 14 steps is too much and she knows what is down here anyways!
 
#32
Update #2. Figured out what's giving me some trouble. The wiring coming from the loco back into the tender was hindering the drawbar. BVroke down the two today, made sure wires were clear of everything and voila! She circumnavigated 11"ish radius track!! I'm super stoked. Placed a small piece of plasticard on the tender to keep the wires away from the drawbar. Waiting on the glue to dry and I'll run the circle again to ensure all is good and will stay that way. Next is the tunnel build......
 



ModelRailroadForums.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com