12" working railroad

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Topics may include: antique park gauge train restoration, preservation, and history; building new grand scale equipment from scratch; large scale miniature railway construction, maintenance, and safe operation; fallen flags; track, gauge, and equipment standards; grand scale vendor offerings; and, compiling an on-line motive power roster.
rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Wed Nov 13, 2019 1:58 am

Here I've got the hydraulic motor bracket fit up to the truck for the S12. I need to install the sprocket and weld the bracket to the cross-tube so the motor and sprocket/hub is centered within the truck. The cross tube will remain bolted in, and I'm going to weld a 2 bolt clip to the bracket that will bolt to the bolster. This will allow removal and modifications of the bracket, or changing it outright for a different drive system if needed down the line.
S12truckhyd.jpg

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Tue Jan 07, 2020 4:15 pm

And the project backlog grows haha, I picked up an old Struck mini-dozer through a trade that needs some TLC. The 12HP Briggs flat head has new carb and runs good, but fuel tank is missing so I just ran the engine on a temporary tank. The steel tracks are shot, they have tons of play in the links and are made of some #55 conveyor/mining chain that is not very available anymore and very expensive. I sourced a new set of mini-excavator rubber tracks that are within a couple inches of the same circumference for a good price, and I am going to get some drive sprockets drawn up to match and get them laser cut. The Belt system is a bit hokey so I may see if I can find a second hand mower transmission to use instead. This little guy will work wonderfully (albeit slower) to backfill my foundation and grade my RR's ROW, so I'm excited to get it working again and not blow as much money on rental equipment.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Jan 10, 2020 1:02 pm

I spent Wednesday night disassembling the mini dozer. The drive sprocket bushings on the rear hubs have been replaced, but the front ones were very sloppy. I was a bit disappointed that it's only 1" axles, so I decided I'm going to beef this whole thing up a bit. I ordered 4ea 3500# trailer axle stubs and loaded idler wheel hubs. This way I get tapered Timken type sealed bearings instead of bushings, and I will have the 5 lug bolt pattern to bolt my rubber track sprockets onto so they are easily serviceable. I will need to weld up some "top hats" for the rear so I can adapt the chain drive sprockets to the rear hubs. Parts are about a week out, so pics to come when everything gets here.

LIALLEGHENY
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Re: 12" working railroad

Post by LIALLEGHENY » Fri Jan 10, 2020 1:38 pm

Interesting project dozer you have. I have an old Speedcat Dozer that I have to repair. The tracks are worn out, and the spline on the drive sprocket is stripped. I was thinking about getting rubber tracks as well, so I"ll be curious to see how you adapt them to your machine.

Nyle

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Jan 10, 2020 3:51 pm

I'm not sure how similar the Speedcat is to the Struck?
Mine has the small drive sprockets welded to the drive shafts, I'm not a fan haha.
I am planning to draw up and have laser cut new track sprockets to match the rubber tracks, and then I'll likely have to relocate the front axle forward about 2" as the rubber tracks are about 6" longer circumference than the steel ones. I ordered some 180 x 37 x 72 tracks that were about $280/pair with free shipping, they are for the Kubota micro excavators like the KX-008 and so on.
As for the drive system, I would like to offset the output shafts slightly so I can run the shafts all the way across the body and have pillow block bearings on both sides so it eliminates the cantilevered loads on the shafts. That will require more disassembly to change the belts though, and also will take longer belts for one side so I haven't decided 100% on that yet.
I'm probably going to have around $650 into the swap and upgrades, but should have a more study and serviceable machine when I'm done.

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Wed Jan 15, 2020 10:23 pm

The rubber tracks and "trailer" spindles arrived for the mini-dozer, just waiting on the hubs so I can figure out the backspacing and get the track width right. We have about a foot of snow so they have been delayed in shipping. :(

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Jan 17, 2020 12:08 am

Pic of the tracks and one of the trailer axle spindles. Hoping the hubs arrive tomorrow so I can get moving on the laser cutting for the sprockets and figure out my width so I can cut the 1-1/2" Sch 80 pipe axles to size.
Tracks.JPG

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Thu Jan 23, 2020 11:33 am

Sample track sprocket cut in 12ga to test fit. Actuals will be 3/4" plate.
tracksprockettestfit.JPG

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Fri Jan 31, 2020 1:24 pm

Sprockets got laser cut, and I spent a considerable amount of time with the die grinder and a carbide burr rounding all the edges over to ensure they don't chew up the tracks.
They fit nice, looks like the axle centerline to centerline distance is going to be 36-1/2" tensioned. That is longer than the original "wheelbase", so I'm going to position the forward axle as close as I can to the blade and the rear axle will likely be bracketed to the rear corners of the original dozer body.
The original #40 sprockets just weren't up to the task and the teeth were all hooked, so I'm going to go with some Honda 1000 street bike sprockets in #530 which is directly compatible with #50 (which will be used on the output shaft sprockets).
tracksprocketsfit.JPG

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BigDumbDinosaur
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Re: 12" working railroad

Post by BigDumbDinosaur » Sat Feb 01, 2020 1:46 am

rkcarguy wrote:
Fri Jan 31, 2020 1:24 pm
The original #40 sprockets just weren't up to the task and the teeth were all hooked...
They were likely sprockets with unhardened teeth. If the teeth were hardened the chain would fail long before the sprockets.
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I'm an old guy. What's your excuse? ☻

rkcarguy
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Re: 12" working railroad

Post by rkcarguy » Mon Feb 03, 2020 11:12 am

BigDumbDinosaur wrote:
Sat Feb 01, 2020 1:46 am
rkcarguy wrote:
Fri Jan 31, 2020 1:24 pm
The original #40 sprockets just weren't up to the task and the teeth were all hooked...
They were likely sprockets with unhardened teeth. If the teeth were hardened the chain would fail long before the sprockets.
They seemed like mild steel to me. I know some of the sprockets are made from a better alloy at least.

rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Sat Feb 08, 2020 1:21 am

Sprockets arrived, specs say 1040 steel.
I haven't got much done lately, been suffering from a nasty cold and my area of the state has been attempting to float away due to flooding and everything has been super muddy.
I have a bunch of parts in the "build pipe" though, basically a 4" channel frame with holes in it that the dozer axles will pass through, and then the Struck Dozer body will slip in between and bolt to the channels on each side. The axle centers are going to be about 8" further apart(front axle will actually be sprung forward), making the frame necessary as well as making things much more stable. It didn't take much for the Struck to tip if one tried to put a loader bucket on it, and I may try this eventually so the long wheelbase placed as much forward as I can should help.
I also wanted to let everyone know that I removed a tooth when drawing up the sprocket in CAD and went with the same size track sprocket (11 tooth) as the Kubota Mini Excavators, to attain the longer wheelbase. The tracks would have been much closer to fitting the stock Struck wheelbase with a 12 tooth sprocket.

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