In the Justice League episode "Eclipsed", Wally uses the term in a different way, referring to a ramp created by Green Lantern's ring to run through space towards the sun, in order to plant a device to stop the sun from going out from Eclipso.
Though only seen briefly, the cosmic treadmill did make an appearance in Wally's apartment in Central City during the Justice League Unlimited episode "Flash and Substance."