I like to switch and set out cars along the way, I use a number of different Lionel style uncoupler magnets, both O and O27. The first MTH geep I bought was a PS1 back in 1998, 20-2174-1. This unit worked great and is still a favorite of mine. Through the years I have acquired a number of MTH geeps, they are not all the same. Some roll and switch well and some hang up on the uncoupler magnets. This has always been a pain to me. I have filed down some of the O magnets which helped. I have used a press to push the O27 magnet less than a sixteenth of an inch to lower it to track height, that helps too. The thing about MTH pick up rollers on its geeps is they are always changing.
Today, I looked at all the rollers on the units. I am sure the MTH engineers thought this or that was better, but only one style stands out, the 2 roller small diameter pickup roller. It does not stall on the magnets and it has better electrical pickup, (4 rollers per unit.)
Here’s what I found by year.
1998, PS-1, GP9 20-2174-1 it has Two large rollers with a small insulated mounting pad, Works great, allows the roller to compress way up inside the truck block, almost flush. I have never had a shorting problem with this setup!
2003, PS-2, GP7 30-2353-1 has Four small rollers with a full insulated pad. Works great.
2005, PS-2, GP9 30-2638-1 has Two large rollers on a full insulated pad. It sucks, the roller can only compress into the truck block up to the insulated pad, not quite far enough as it stalls on magnets.
2006, PS-2, GP20 30-2686-1 has Four large rollers, full insulated pad, it sucks, the large rollers will not compress enough inside the truck block before snagging on the magnets.
2011 PS3, GP9 20-20060-1 has Four small rollers on a full pad, works great.
After looking at them, I decided to tinker with them. It turns out that they are all interchangeable! The unit with the small 2 roller pickup always rolled smoothly. What I hope to do is see if I can order some of the pickups with the two small rollers and I think that will solve my switching problems. Then I can use any of the units on the local.
You can see in the photos the different styles and the different size of rollers. Big rollers are bad, multiple rollers are good. It is amazing to see that 1/16 of an inch can really cause issues. (Probably less than that)
Picture 02 , top to bottom, 1998 large 1 roller, small pad, 2005 large 1 roller large pad, 2011 small 2 roller
Picture 08, shows the 2005 large 1 roller, large insulated pad, the pad is too thick and prevent roller from compressing into the truck block.
The botttom is the 1998 large 1 roller with small pad, it allows the roller to compress just a bit more with no problems.
Picture 10, shows the 2011 small 2 roller pickup and pad, nice!
Picture 13, shows the 2011 small 2 roller pickup on top, the 2006, large 2 roller pickup on bottom, You can see the difference in diameterand I think the 2011 is a tad wider. Those large rollers will not compress enough and hang up on the magnets.
Dan