TheRailwire
General Discussion => N and Z Scales => Topic started by: CNR5529 on March 09, 2016, 03:41:15 PM
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The newer passenger trucks by MTL have an offset bolster. Does anybody know what the amount of offset is? Unfortunately, this is not an easy dimension to measure accurately, as one needs to measure from the center of the bolster pin to the center of the middle axle. Similarly, does someone know the dimension from top of rail to the top of the bolster pin? I have not found these dimensions in any literature on the MTL website. Thanks in advance!
Fredrick
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The bolster hole is centered between the middle and outer axle, so you can measure between the centerlines of the journal boxes and divide in half to get the offset. I haven't had reason to measure the bolster height since the models ride at the correct height above the rail.
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This drives me crazy. I have spent the last two days looking for 100T roller bearing trucks to retrofit my cars. No one has a comprehensive list of what cars require 100T trucks... Sure tank cars are a given. But Cryogenic reefers? Who knew? What about 52' gondolas?
And then there are the trucks. MTL makes a 100 RB truck, but you can't buy it. And there are conflicting reports wether it has a center kingpin hole or offset.
Trainworks has nice trucks but they are offset so I can not use them on most applications such as MTL's centerflows.
BLMA has great 100T trucks, if you can find them... and if the models ride high.
Atlas 100T trucks? $5 a set and you need to replace the wheels. And then you have a coupler you can not use if you want to go body mount.
Can't we just have proper 70T and 100T trucks without couplers and with lo profile metal wheels without the fancy offsets and sunken bolsters?
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Can't we just have proper 70T and 100T trucks without couplers and with lo profile metal wheels without the fancy offsets and sunken bolsters?
You had me until the last part. Lowered truck bolster is one of the great advances we've had in freight cars the last 10 years.
Jason
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Agreed, lowered bolsters were a revolution! So simple to add washers if you need to raise a car, not so simple to lower.
Mark
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Washers are the way I'd go if all I could get were the low bolsters. Get some paper punches from the office supply store and punch your own from styrene sheet. 1/8 and 3/16 punches make a nice washer, or you can drill the hole the exact size you want and them punch out the washer.
I've used Atlas trucks with both the plastic and metal wheels and they both work fine for me. As for the couplers, I cut them off, then recycle them to make cushion underframes and body mounts for tank cars.
On the MT, I suspect that they make it with both centered and offset holes. I've found other MT trucks with centered holes, when the only ones of that type advertised have offset.
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The medium-extended coupler pocket (the one used for the B-end of the drop-end gondolas) has a centered bolster hole. All the other four-wheel trucks, with or without coupler, have an offset hole.
Back under the Kadee banner, the diecast 50' boxcar underframes compensated for the offset hole, but that went away with the two-part underframe enhancement. Currently, I don't believe any of the models allow for the offset bolster hole. Possibly the 89' TOFC/COFC and the open-frame auto rack if the trucks are rotated 180 degrees.
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The bolster hole is centered between the middle and outer axle, so you can measure between the centerlines of the journal boxes and divide in half to get the offset. I haven't had reason to measure the bolster height since the models ride at the correct height above the rail.
Thanks for the info, but I don't think this is correct. The bolster hole is closer to the center axle than to the outer axle:
(http://www.spookshow.net/trucks/mt6pass.jpg)
Using a ruler, it looks like the hole is roughly 1/8" or 5/32" from the center, but this measurement was not very accurate. I am looking for this dimension and the height above top of rail of the bolster because of a passenger car project I am working on that will be 3D printed. The bolster pin needs to be located such that the truck gets mounted at the right position relative to the frame.
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I don't have a truck frame handy, but your photo isn't straight-on at the bolster hole. I'm guessing you don't have digital calipers handy to take the measurements?
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The newer passenger trucks by MTL have an offset bolster. Does anybody know what the amount of offset is? Unfortunately, this is not an easy dimension to measure accurately, as one needs to measure from the center of the bolster pin to the center of the middle axle. Similarly, does someone know the dimension from top of rail to the top of the bolster pin? I have not found these dimensions in any literature on the MTL website. Thanks in advance!
Fredrick
Fredrick,
The offset is .1500 in" and from top of rail to top of bolster is .2375 in". Hope this helps.
You are also right that the offset is NOT centered between the axles.
Jon
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Fredrick,
The offset is .1500 in" and from top of rail to top of bolster is .2375 in". Hope this helps.
You are also right that the offset is NOT centered between the axles.
Jon
Thanks Jon, that is exactly what I was looking for.