The Track Scrubbing Car has a solid metal car body, with a metal pipe affixed to the top with a screw through the bottom. There are decorative elastic straps and braces holding the pipe as well, providing a more believable appearance to the load.
There are two stainless steel pins for the rollers mounted beneath the car. The angle and height of these pins are adjustable with a wrench.
The pins hold paint rollers, specifically 2-inch fine finisher refills. The car came with 4 rollers. The rollers can be cleaned and replacements can be purchased at any big box hardware store I imagine.
The car has diecast sprung trucks.
The scrubbing concept relies on the rollers being angled to cause a combined rolling and dragging motion. Because of the angle, the rollers roll slower than they would be if they were set perpendicular with the track. This relative slowness of the rolling results in the roller dragging somewhat along the rails thereby scrubbing the rails. The rollers also roll at an angle across the track and therefore scrub the track laterally as well. Watch the scrubbing action in the video below.
The car worked well for me. However, as explained in the instructions, setting the rollers too low "may cause the car to split a switch and derail." This was a regular occurrence when exiting my ScaleTrax 072 and No. 4 switches heading to the right. The point rails on ScaleTrax do not have a very strong spring bias to hold them in place. This allows the passive non-derailing function. As the car is proceeding through the switch to the right, the back roller pushes the point rails to the right just long enough to allow the trailing truck to track to the left. Reversing the orientation of the rollers causes the opposite to happen; derail when exiting the switch to the left.
The instructions state that raising the height of the rollers can alleviate this occurrence. Adjusting the angle may help too. Fortunately, on my layout, I can run the car on two of the three loops without encountering this situation, and I encounter it at only one switch on the third loop. So I will not be changing the height of the rollers, since I imagine this will affect the cleaning performance.
A well planned route could avoid this issue on some layouts. Others will have switch tracks on which the points are not so easily moved. Still others will need to address this through tuning the height and/or angle of the trailing roller.
I am satisfied with this car. The dragging, lateral scrubbing action, and the absorbent sponge rollers do well in removing the grime. The fact that the rollers are readily available is a definite plus as well. The build quality tells me I will have this car for a long, long time.
See the patent: U.S. Patent No. 7,597,049
