Z Scale SD70's showed up this weekend!

I got mine Saturday.


They look great! Real fine detail! They are even more beautiful in person than in the photo's. The paint and detail is simply stunning! There is even a cab interior, and windshield wiper detail molded on.



I ran them on a test loop of MTL roadbed track, which is the tightest radius I think they can run on. There is a bit of coupler swingover, but not enough to derail a truck mounted coupler MTL car.

I inspected under the shell for room for a DCC decoder, and measured .27" wide, which is a bit too narrow, even for a Lenz Gold Mini tipped diagonally.

The light board has solder points for attaching a decoder, and it is just a matter of time till some manufacturer offers a thin decoder that will fit, so I would recommend not even trying to take the shell off until such a decoder is available.

I put them on the test track and ramped up the voltage. At 2 volts, the headlight came on, and the loco started to creep, but so slow I did not bother to measure.

I had to run them for 30 minutes at 5 volts to loosen up the mechanisms, as they did not all run the same speed at first.



One loco ran a lot slower than the other 2, so I measured the current, and found it was drawing 95 milliamps. The other two were drawing 70 milliamps.

I was concerned about this last night, but this morning they all performed the same after the 30 minute burn-in consisting of running forward for 15 minutes, then reverse for 15 minutes. I took the shell off the one that had been drawing more current than the others and checked for motor heat, and was suprised the motor was running cool.

Being curious, I did a complete disassembly just to see what's what. Let's just say, you don't want to do this, ever! The frame is held together by 3 frame clips, 1 of which is the fuel tank. It's super fragile! I was extremely careful, so I did not damage mine, but I seen cracks develop while unbuckling the tank halves.
Just to be safe I filed the buckle nubs to half their thickness on one half of the tank, and used a paintbrush to apply some Tenax 7R to repair the cracks in the buckle side of the tank latches, and let it sit for an hour to harden.



I measured current draw on the motor itself at 8 volts to be 20 milliampes, and with the frame halves together but no trucks installed, 50 milliamps. I was able to carefully put everything back together, and it ran when I got the shell back on.

After burn-in I equaly spaced them around the test loop ramped up to 5 volts, and observed about 30 scale MPH, and they all held the same relative positions for about 5 loops till one started catching up to another, then I lashed them up and ramped voltage to the limit of 8 volts I observed about 60 SMPH.

I measured individual currents at 68 to 73 milliamps so I am happy the slow loco worked itself into the population, and can be MU'd just fine.

Last night I was not super happy, but today after burn-in I am a happy camper. What would I recommend when you get yours? Run them at 5 volts, both forward and reverse for 1/2 hour to loosen them up, and don't try to take the shell off, as it's kind of hard and risky.

I don't have a layout to test pulling power, but they have a traction tire on the rear truck, and should pull fine.

 

Robert, you are not suppose to run the engines in stripper colors. Its nice to finally getting reliable internet service. The other hotel din't have internet service, so I wasn't able to order mine before Rob when on vacation. I cancel my original order thinking that I can wait for the BNSF version, buuuuut I am not so sure anymore.

 

Hi Tony, I just used af Fluke 77 meter in series with one lead off the power pack connected to the test track.

 

I can tell you, these engines do not speed match any other Z Scale engine ever before produced.

 

I do have 4 F59PHI's, and they do run slower than other Z locos too, but I have only ever ran them with their passenger trains before.