Underfloor Truck Tests Conducted by Tony Tieuli.

The sled running with no weights:

• 8v, less than 1/4amp, slow speed. Negotiates entire layout until subway ramp. Notching up to 10v gets it over the hump.
• 12v. free running everywhere at speed higher than regular Q truck under EMASS 4300 car with 33 inch wheels.

Layout has 10-12" radius curves - two with a double-track Y to negotiate (creates drag) Grade on subway is 78 inches long (6.5 feet) rising 7 1/4 inches from lower level to top. You do the math on the % of grade as I've forgotten. It is steep, however. Editors Note: about 9.30%.

Now for the weights.

• 1 lb weight: Full 12 volts at 1/4 amp to negotiate flat layout at about 30-40-mph. Will not come out of subway.
• 14 oz: Full 12 volts to come out of subway -no stall (10mph) - 1/4 amp. 10-11 volts to negotiate rest of layout at 30-40 mph.
• 12 1/2 oz: Full 12 volts to come out of subway - no stall (10mph) - 1/4 amp. Ten volts to negotiate rest of layout at 30-40-mph.
• 6 oz: Ten volts to come out of subway -no stall (10mph) - 1/4 amp. 9-10 volts to negotiate rest of layout at 30-40 mph.
• 3 oz: Nine volts to come out of subway - stalls at top of ramp. 9-10 volts to negotiate rest of layout at 30-40 mph.
• 3 oz Ten volts to come out of subway without stall. 9-10 volts to negotiate rest of layout at 30-40 mph

You can see that from 0-6oz, you need 10 volts to get out of the subway. Then it goes from 10-12 volts for 12-16oz loads. I am not familiar with the ratings of motors, torque, etc., but this motor seems to do the job ok and is more than adequate for urethane or plastic models. I hope this study is clear enough for you.

Editors Note: Tests were conducted using a flat car that Tony could add weight to. It is referred to as the "sled".