Upgrading GN 1246

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twforeman

Certified Great Northern Nut
So I have this 1980's vintage Tenshodo model of a GN Consolidation. It's a pretty nice looking model so a while ago I replaced the motor and installed a Soundtraxx DCC decoder. But it never really ran very well.

So a couple of weeks ago I took it apart and ran some tests. I was thinking that the motor was pulling too many amps and that was the problem, but I tested it and it never pulled more than 500 milliamps, so that wasn't it. So I started looking at other things.

I decided that the electrical pickup on the tender was probably the issue. I had added wipers to the trucks that came with it, but the electrical path was pretty crappy. And the trucks rolled like crap. Lots of friction.


So I decided I'd replace the trucks and redo the pickups. But what trucks to use? The ones that came with the model were a Commonwealth style truck, and the photos I was looking at showed the same. But try and find a reasonable Commonwealth tender truck out there...

After looking around for a while I looked over at the Bachmann GN Consolidation I had. It's a cheap, not very accurate model that I bought a long time ago. It was never going to run on the layout. But it had the correct trucks on the tender!

So, even though they were the snap-in type trucks I decided to use them. I cut off the snap-in part and drilled a hole in them for a screw. Then I had to make some bolsters for the tender, so I glued up some styrene strips and epoxyed them into place.


I centered them on the existing truck mounting holes.


Next was the electrical pickup. I have a bunch of Intermountain metal wheel sets and I saw in this forum post about using brass tubing for pickups so I decided to try it.


I ended up having all the electrical pickup in the tender trucks. I was going to use the locomotive wheels for one side, but I forgot to connect the wire.

I put it all together, but it still didn't work very well - it kept cutting out. So I cleaned the wheels and axles with mineral spirits and pinched the tubes a little bit to get better contact. It improved but it was still cutting out.

But, in anticipation of this project I had purchased a CurrentKeeper to install. I needed to make some more room in the tender to mount the CurrentKeeper so out came the Dremel.

Before:


After:


Lots more room. After installing the DCC decoder and the CurrentKeeper it looked like this:


And this is how it performs now:

I'm pretty happy with it now.
 

Espeefan

Well-Known Member
Nice to see another brass tinker on the forum. Glad you got it running. I notice from the brass peeking through the wheel plating this thing has a few scale miles on it, so it's run well in the past. :) I've had similar issues with balky electrical pickup. Let me preface this by saying I'm not Monday morning quarterbacking your work. I've been there done that! It's all part of learning brass. This is just technique sharing/advice for you & others who might have similar issues

I usually do the following:

1: If you have another tender substitute it and see if the issue is still there. If you don't have another tender, clip a long test lead to the drawbar and the left rail. See how she runs that way.

2: I have a meter that sounds an audible tone when I set it to check for continuity. Clean all wheels first of course, as well as the bolster contact surfaces then flip the tender over and with one lead on the kingpin, check each wheelset. If the tone cuts in and out when you touch each pickup wheel and move it, disassemble the trucks and clean the axle pockets. I once had a Westside Pacific that had both the bolster surfaces painted, as well as the insides of the tender trucks, insulating everything!

3: Don't forget the drawbar connection. Sometimes these loosen over time, which will cause disruption. Other times that little wiper soldered to the drawbar is loose or missing. It is vital to good contact. It may need to be re-soldered, or replaced. I use phosphor bronze wire here, it's springy and better at holding tension.

4: If you're still having issues, it may be an intermittent short. I turn out the lights in the layout room and run it, and look for arcing along the running gear & tender. Your model has plastic brake shoes. Sometimes these are brass, and if they aren't aligned perfectly they'll cause shorts. Once I had a lead truck contacting a coupler box screw just enough to cause jerky running.

5: Don't forget your track. Dirty rail and unpowered switch frogs will absolutely kill a short wheelbase loco. 0-6-0's, 4-4-2's and some 0-8-0's and 2-8-0's can be susceptible. The loco picks up right rail, the tender picks up left. This generally works fine with DC but you can get issues with DCC, especially with sound. I know guys who add auxiliary pickups to all wheels, using strips of PC board and phosphor bronze wipers. The bigger the current path, the better.

I'm thinking going straight to the keep alive would have solved your problem without the other mods. A few guys in my club just automatically install them on short wheelbase brass. Live & learn. Brass will teach you patience! It's rewarding to get them running though, isn't it?.

BTW, I love the cast bullets in the tender. Are you a reloader as well?
 

twforeman

Certified Great Northern Nut
Nice to see another brass tinker on the forum. Glad you got it running. I notice from the brass peeking through the wheel plating this thing has a few scale miles on it, so it's run well in the past. :) I've had similar issues with balky electrical pickup. Let me preface this by saying I'm not Monday morning quarterbacking your work. I've been there done that! It's all part of learning brass. This is just technique sharing/advice for you & others who might have similar issues
No worries on the critiquing. I welcome feedback. I'm also glad I got it running, it's a nice little engine. I bought it on eBay so I have no idea how many miles it has on it.

I usually do the following:

1: If you have another tender substitute it and see if the issue is still there. If you don't have another tender, clip a long test lead to the drawbar and the left rail. See how she runs that way.
This is my only steam loco currently, so no spare tenders. But that's a good quick test.

2: I have a meter that sounds an audible tone when I set it to check for continuity. Clean all wheels first of course, as well as the bolster contact surfaces then flip the tender over and with one lead on the kingpin, check each wheelset. If the tone cuts in and out when you touch each pickup wheel and move it, disassemble the trucks and clean the axle pockets. I once had a Westside Pacific that had both the bolster surfaces painted, as well as the insides of the tender trucks, insulating everything!
I have a meter like that, and I did some continuity testing. The main reason I replaced the trucks was because the ones that came with it had a lot of rolling resistance and were not really very good. And the original trucks didn't really disassemble - I would have to bend the frame to get the wheels out.

3: Don't forget the drawbar connection. Sometimes these loosen over time, which will cause disruption. Other times that little wiper soldered to the drawbar is loose or missing. It is vital to good contact. It may need to be re-soldered, or replaced. I use phosphor bronze wire here, it's springy and better at holding tension.
When I originally installed DCC I removed the drawbar power connection. Due to the fact that the decoder is in the tender the drawbar wasn't really useful anymore.

4: If you're still having issues, it may be an intermittent short. I turn out the lights in the layout room and run it, and look for arcing along the running gear & tender. Your model has plastic brake shoes. Sometimes these are brass, and if they aren't aligned perfectly they'll cause shorts. Once I had a lead truck contacting a coupler box screw just enough to cause jerky running.
It seems to be running pretty consistently now.

5: Don't forget your track. Dirty rail and unpowered switch frogs will absolutely kill a short wheelbase loco. 0-6-0's, 4-4-2's and some 0-8-0's and 2-8-0's can be susceptible. The loco picks up right rail, the tender picks up left. This generally works fine with DC but you can get issues with DCC, especially with sound. I know guys who add auxiliary pickups to all wheels, using strips of PC board and phosphor bronze wipers. The bigger the current path, the better.

I'm thinking going straight to the keep alive would have solved your problem without the other mods. A few guys in my club just automatically install them on short wheelbase brass. Live & learn. Brass will teach you patience! It's rewarding to get them running though, isn't it?.
I did add phosphor bronze wipers to the original trucks when I first added the DCC decoder.

The track is pretty clean, my DCC diesel loco doesn't have any issues. I'm sure it could be cleaner. You are probably correct that installing the CurrentKeeper earlier would have solved the issues, but I really wasn't happy with the tender trucks anyway.

On this loco only the tender is currently picking up power now. One wheel on each truck picks up from each rail. With the CurrentKeeper it seems to be working out well.

BTW, I love the cast bullets in the tender. Are you a reloader as well?
I am. I cast my own bullets and reload. I found that the bullets also make great weights for freight cars (and tenders.)
 

trailrider

Well-Known Member
No worries on the critiquing. I welcome feedback. I'm also glad I got it running, it's a nice little engine. I bought it on eBay so I have no idea how many miles it has on it.



This is my only steam loco currently, so no spare tenders. But that's a good quick test.



I have a meter like that, and I did some continuity testing. The main reason I replaced the trucks was because the ones that came with it had a lot of rolling resistance and were not really very good. And the original trucks didn't really disassemble - I would have to bend the frame to get the wheels out.



When I originally installed DCC I removed the drawbar power connection. Due to the fact that the decoder is in the tender the drawbar wasn't really useful anymore.



It seems to be running pretty consistently now.



I did add phosphor bronze wipers to the original trucks when I first added the DCC decoder.

The track is pretty clean, my DCC diesel loco doesn't have any issues. I'm sure it could be cleaner. You are probably correct that installing the CurrentKeeper earlier would have solved the issues, but I really wasn't happy with the tender trucks anyway.

On this loco only the tender is currently picking up power now. One wheel on each truck picks up from each rail. With the CurrentKeeper it seems to be working out well.



I am. I cast my own bullets and reload. I found that the bullets also make great weights for freight cars (and tenders.)
And it is very easy to determine how much weight you are using. Just divide the bullet weight in grains by 7000 and multiply by 16 to get the weight in ounces.
For example, a 250 gr. bullet = 250/7000 gr. per lb x 16 oz per lb. = (250/7000)x16 = 0.57 oz. Just depends on what bullets you have and how much room you have in your car/tender/etc.
 

twforeman

Certified Great Northern Nut
And it is very easy to determine how much weight you are using. Just divide the bullet weight in grains by 7000 and multiply by 16 to get the weight in ounces.
For example, a 250 gr. bullet = 250/7000 gr. per lb x 16 oz per lb. = (250/7000)x16 = 0.57 oz. Just depends on what bullets you have and how much room you have in your car/tender/etc.
Or, you know, I could just put the car/tender/whatever on the postal scale and add bullets until it's the weight I want. :)
 

flyboy2610

Loveably weird
Glad you got it running! Are those tender axles coated or plated with something? Make sure the coating isn't interfering with the pickup. I also learned (the hard way) that the wire needs to be small diameter stranded wire that's quite flexible. Otherwise the wire can cause issues with the wheels not making good contact with the rails.
 

twforeman

Certified Great Northern Nut
Glad you got it running! Are those tender axles coated or plated with something? Make sure the coating isn't interfering with the pickup. I also learned (the hard way) that the wire needs to be small diameter stranded wire that's quite flexible. Otherwise the wire can cause issues with the wheels not making good contact with the rails.
They look coated but they seem to be working out okay.

The wire I used is 30ga and very flexible.
 

Sirfoldalot

Curse You, Red Baron!
Staff member
WOW ... what a great lesson! Thank you all for the information.

Love the loco, Tom!

ALAN - Take a video lesson with that 2-10-4! BAHAHAHAH! :D
 




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