Are the Burlington A and B units out yet? If not, when will they be available?

We're running a Bachmann Steam Locomotive ("HO" USRA 0-6-0) and using Williams (by Bachmann) Smoke Fluid. We put 15 drops in the stack and ran it around the track at a fairly high rate of speed, then slowed it down, and slowed it down more, but nothing much happens... it smokes a little bit once or twice. The pamphlet/instructions don't give any information regarding how much smoke fluid, or what kind, to use.