The time trials I did yesterday with my Marx 999 locomotive produced some interesting results. First let me describe the test rig. I have a loop of 0-31 gauge tubular track, and the total center-rail length is 13.4434'. I have a 275 watt Lionel ZW transformer, and I have power applied in two separate equidistant points along the line. I have a digital multimeter to monitor the track voltage. I used a lock-on to connect the red and black probes. I have an inexpensive clamp-style amp meter to monitor the amperage from the hot wire between the transformer and the track. I also have a 10 turn loop in this hot wire to improve the accuracy of the amp readings. For the time trial, I used the stopwatch feature of my Android phone, and timed the train over 5 laps. I tested just the locomotive at 5.5 VAC, 6 VAC, 6.5 VAC, and 7 VAC. Outside of this narrow band, the locomotive either would not move or would move so fast I was afraid that I'd derail and damage the 80+ year old antique. I then connected a tender, three freight cars, and a caboose and repeated the time trials at 7 VAC, 7.5 VAC, and 8 VAC. This band is even narrower, and again the train would not move at less than 7 VAC, and would run too fast beyond 8 VAC. Below is the velocity calculations and amp draw:
Locomotive Only:
| TRACK VOLTAGE | Elapsed Time MIN | Speed FPM | Motor RPM | Speed MPH | Scale MPH | Amp Readings | Power Watts |
| 5.5 | 1.1422 | 58.8508 | 880.3 | 0.67 | 42.8 | 1.68 | 9.24 |
| 6 | 0.7260 | 92.5854 | 1384.9 | 1.05 | 67.3 | 1.71 | 10.26 |
| 6.5 | 0.5912 | 113.7036 | 1700.8 | 1.29 | 82.7 | 1.77 | 11.505 |
| 7 | 0.4160 | 161.5793 | 2417.0 | 1.84 | 117.5 | 1.86 | 13.02 |
Locomotive pulling five cars:
| TRACK VOLTAGE | Elapsed Time MIN | Speed FPM | Motor RPM | Speed MPH | Scale MPH | Amp Readings | Power Watts |
| 7 | 1.0458 | 64.2733 | 961.4 | 0.73 | 46.7 | 2.1 | 14.7 |
| 7.5 | 0.5832 | 115.2634 | 1724.2 | 1.31 | 83.8 | 2.12 | 15.9 |
| 8 | 0.4375 | 153.6389 | 2298.2 | 1.75 | 111.7 | 2.2 | 17.6 |
The most interesting finding is at 7 VAC, the locomotive alone was running at 117.5 MPH (scale), drawing 1.86 amps, 13.02 watts. When I attached the cars to the locomotive and ran it at 7 VAC, it slowed down to 46.7 MPH (scale) drawing 2.1 amps and 14.7 watts. One thing I should point out is that my amp readings would usually spike when the train was on the curve sections, so my amp readings are sort of a composite. It seems as though the majority of the power was consumed just moving the locomotive. The locomotive weighs 1 lb and 12.1 ounces, and the mechanical efficiency of the gear train is typical - i.e. not so good.
