I bought an actual HO track inspection car - three pieces of transparent plastic - body and two bolsters glued together and tapped for the trucks. The trucks are metal Kadees. The body is as long as a 40' boxcar, but the trucks are mounted so that the lead and trailing wheels are beyond the plastic body. The whole thing weighs one oz. I'm wondering if adding weight to the center - between the trucks so that the car replicates actual car weight, yet you can watch the action of the wheels, would be a good idea.
Gene
Gene
I made mine out of plexiglass from the hardware store, they cut it for me. I didn't extend the trucks outside the floor, that is probably a good idea.
It was suggested to me last year that the test car should be weighted to NMRA specs. My car is 4 ounces and seems to be just right. It helped me to see what the problem was with the turnouts, too large a gap for the transition area, especially after Sheldon posted a picture from NMRA.
Bob
That's what I'm thinking. When I have time I can paint the weights and the sides and store it on the MOW track in South River Yard, after that gets built. It doesn't have couplers as the builder suggests that pushing or rolling it through the inspection area is the best method.
Gene
When I first made the car, I didn't add any weight. By pushing it with a finger through the turnout with a little down pressure, I could feel and hear the dip in the frog flangeways.
I had some leftover weight bars with holes, I fastened them with screws so they could be removed. One could also glue little posts on top and just lay the weight on loose.
Bob
What the heck are you guys talking about? Sounds like a glass bottom boat! Can you really see the sore spots with this contraption? with the height and depth of my track, I will need a mirror angled on on side, but I'm open for any ideas like this one. I think I have some plexi glass laying around somewhere....
Tony
Well, it is sorta like a glass bottom boat. A test car is just a piece of clear plastic with trucks mounted on the bottom. Pushing it through turnouts or curves, you can detect small problems like track misalignment, wide flangeways in turnouts that cause the wheels to dip, or wheel flange hitting the frog apex.
By pushing down a bit with your finger, you can feel the slightest imperfection. The idea of the clear plastic is to see the wheel action, but I've found the sense of touch to be more effective with my poor vision. It actually also involves hearing , so you have 3 senses to detect problem areas.
Cut the plastic 1-1/4" wide and about 6" long. Add 3/16" styrene cross pieces for the bolsters. Drill a 1/16" hole center of each bolster, tap 2-56 for a 1/4" machine screw.
Install any truck with metal wheels, with a .010 shim washer between the bolster and truck. I tapered the bolsters on mine so the truck has more clearance to tip and swivel. You can add Kadee #148 couplers but serves no purpose. The 3/16" bolsters will make the coupler height pretty close.
Gene said his test car had the trucks mounted so one wheelset stuck out beyond the ends, sounds like a good idea also. I just mounted them inset a bit and seems to work fine. I did add couplers and set a leftover box car body on it, with some weight.
I tried using Kadee sprung trucks, but the springs dampened the feel, so I switched to plastic trucks. The first detection is by feel, then you can get down for a close visual check. I was constantly getting derails at one turnout, and finally found the problem using the test car.
Bob
Tony,
Search eBay with "track inspection car" if you don't have the tools to cut the plexiglass or can't find the scrap.
Bob - I hadn't thought about using plastic trucks instead of metal. I just might change trucks.
Gene
For the price, it's hard to beat the one Micro-Mark sells.
http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82414 (http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82414)
(http://www.micromark.com/prodimgs/82414.jpg)
Sid
Gene
I guess it was the equalizing effect of the Kadee trucks that kept me from feeling the dip. Even with the plastic trucks, if the mounting screw allows excessive sideways rocking of the truck it lessened the feel.
By moving the car rapidly back and forth over the area, the "click click" became more of a "bam, bam", very audible.
The wonder of the human system, when the sense of sight diminishes, other senses are heightened. I just had another hair-brained idea, how about mounting a stethoscope on the car, or a wireless vibration sensor and seismograph? My initial trackwork would have been a "10" on the Richter scale.
Bob