Locomotive rolling base/track

[Lockwood]

I need to find a base or track that I can test my locomotive on, one that has like rollers located were the locomotive wheels are placed. I have looked on the web and found Jak Rollers, but the website does not exist anymore. Is there anyone that could help me on this problem or tell me of other products that are out there.  Thank you. 

[dougdagrump]

Here's a few, some fancier than others  and some more expensive than others:

http://www.micromark.com/O-GAUGE-LOCOMOTIVE-ROLLERS-ASSEMBLED-SET-OF-4,8530.html

http://collectorschoicetrains.com/rollertestunit.htm

http://railroadgalaxy.ecrater.com/p/18369883/lionel-o-gauge-operating-roller-base

http://www.bachrus.com/runningstands.php