Great Northern GE 44 ton Center Cab Electric restoration

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Pontiacguy1
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Pontiacguy1 »

I still say that you will have issues with that. It will still tend to lift the axle vertically, but with your setup it will lift the rear axle when you are going forward and the forward axle when you are going backwards. Here is a quick sketch of what I would do if it were mine. You may have to move your sprocket around and even add another idler so that your chain doesn't interfere with your bolster, but this is the way I would do it. A rigidly-fixed idler sprocket with a ball bearing in the middle of it will give you a very long and trouble-free life.

Just give it a look and you can see that it will make your chain slack issues much better, will always pull front-back on the axles when under power, and will give you plenty of ground clearance.
20210128_073111.jpg
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makinsmoke
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by makinsmoke »

Actually I think the bigger circle at left is the gear. Motor in center.

He could get away with one idler gear/shaft below the deck. Chain from the upper gear to the idler, then a sprocket and chain from the idler to one axle, then the pair of sprockets he now has on each axle chain driving one axle with the other.
Pontiacguy1
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Pontiacguy1 »

I drew it the way he drew it... Motor on the left, gear reduction shaft in the middle or near middle. That's what I was saying about positioning: Move things around so that your chains clear your bolster, and then the bottom part, between the axles, put as close to that drawing as you can. Just some way to get it to not pull vertically on the axle when you are in hard pull. You could move the gear reduction jack shaft over to the right and add another idler pulley nearer to the motor to effectively make a 'box' right up above the bolster with the chain, giving the chain enough clearance. Something like that would be what is needed, so that everything has clearance and better angles. I don't have the trucks and body right in front of me, so I have no idea what will actually fit and work and what may have something else in the way. I'm just trying to throw out ideas... maybe one of them will actually help.
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makinsmoke
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by makinsmoke »

Agree.

I was looking at his first few photos of his mock up.

“It’s solvable,” Danny Glover, movie Shooter
Glenn Brooks
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Glenn Brooks »

Pontiacguy, Great improvement. Thanks! Iam sure there is clearance in the truck for two idlers. So I’ll go this route. may be possible to attach the idler arms directly to the underside truck frame or bolster.

I also want to add brakes to both trucks, so probably going to complicate the design with brake rigging intertwined with the chain line... good to plan it now, rather than latter...


Glenn
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

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Glenn Brooks
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Glenn Brooks »

This afternoon, incorporated Pontiacguy’s suggestions into the mock-up. Looks like it will work out well. Pictures tell the tale. The chain line pulls at 90* to the nadir- so torque is directly rearward, with no upward pull on the axles. Also, the chain easily clears the bolster and provides for truck rotation.

An added benefit, the two idler brackets will stiffen the truck frame significantly. So, time to order the sprockets and chain, and build out the truck.
C93B1CE7-7393-4F17-BC85-118C71E258BE.jpeg
Closeup of idler.
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Reverse side of idler bracket. This will be made from one piece of 3/8” plate, with the idler axle welded to the tab at the bottom.
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As they say in the Machining game: Clearance is clearance!
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I will say, building a plywood mock-up really is a valuable, rapid prototyping method.

Glenn
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Pontiacguy1
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Pontiacguy1 »

I would probably pull the idlers towards the middle a bit more if you have the room, just to give more chain length for up and down movement of the axles when you are going over rail joints, dips, and switch frogs. Otherwise, I like that much better than before, and I think your low-speed performance will be a whole lot better than it would have been.
Glenn Brooks
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Glenn Brooks »

Ok, I’ll see if there is room. Chain is only 1/2” away from the bolster when hard over. Although, might not need a 15’ turning radius :D

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Glenn Brooks
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Glenn Brooks »

Well I think Iam back to square one - in a good way. Woke up in the middle of the night with the idea to flip the motor to the opposite side of the truck and move the jack shaft from the center of the truck rearward to the axle. and run a full length jack shaft across to the driven pulley. Discovered this allows the chain line to clear the bolster on one side of the truck and drive the front axle in a simple L shape, with only one idler. I think I’ve beat this to death. Time to start building,.. Diagram is easier to explain...
F32672BD-CED5-4D62-8598-D4F8DF29A84D.jpeg
Which leaves a very simple set up! Motor to jack shaft to starboard. Drive chain to port. Both axles connect down the middle.
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Also noticed, if I notch the mounting plate, I can move the jack shaft and reduction gear down and inboard of the edge of the base plate, and loose the 6” of risers.
BFB876FA-AE68-4B6E-B4C2-B504EDA820CC.jpeg
This seems a lot more efficient, with substantially less fab work and alignment issues.

Glenn
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
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NP317
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by NP317 »

I think you are making progress!
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by rkcarguy »

Glenn Brooks wrote: Thu Jan 28, 2021 3:00 pm Pontiacguy, Great improvement. Thanks! Iam sure there is clearance in the truck for two idlers. So I’ll go this route. may be possible to attach the idler arms directly to the underside truck frame or bolster.

I also want to add brakes to both trucks, so probably going to complicate the design with brake rigging intertwined with the chain line... good to plan it now, rather than latter...

Glenn
Glenn, this is where my build is at as well. I have all the sprockets welded onto the keyed hubs, but have not keyed the axles yet because I need to work around the brakes and I'm not sure what I'm going to use yet. The mini-bike and go kart stuff is just too light in my opinion for stopping half a ton of locomotive, and most other stuff is simply too big to fit. I'm thinking I may try Honda Civic rear disc calipers (they have the lever arms for manual activation for the e-brake), and then make my own discs. With the disc diameter being smaller, it may wear a half moon shape into the pads until they touch, but I would think that would take a long time to happen. I need to have a look at one and make sure they are "shallow" enough to be able to mount on a 6-1/2" max disc without interfering with the axle.

I like your latest version of drive arrangement, gets the job done yet will allow the whole truck to drop out from the underside without removing any chains/mounts etc.
Glenn Brooks
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Re: Great Northern GE 44 ton Center Cab Electric restoration

Post by Glenn Brooks »

Ryan, one local train guy I know just finished building a steam engine. He added a round friction brake to one axle, with a pull to stop handle. Ala manual go kart strap brake. He’d turned the brake drum on his lathe to fit the size and scale of his drivers and under frame clearance. Probably will do this as a parking brake.

Also am getting ready to fab up some traditional locomotive brake rigging, using 2.5” scale cast brake shoes. You could water jet these easily in bulk, and glue or rivet some 1/8” friction material to the contact surface. The rigging mechanism just needs pressure air source, brake valve, and a clippart air cylinder to make them work.

Here’s a sketch of the brake rigging schematic. Pretty easy fab job, looks like.
403AF9FF-7306-448A-AC42-8DC6E7DA51E5.jpeg
Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
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