Suspended G - the rest of the story

Now I have previously showed you the construction and setup of the suspended railway. As the photo above shows, I was able to run the Aristocraft passenger set I had acquired and it looks very nice. The surprise came after running the train for 8 to 10 minutes when the whole thing just stopped. I had initially used a small Bachmann transformer from a G-scale set to get things running. This little transformer is a variable voltage device and has a maximum output of 11 VA at 17 Volts DC.

Basic Bachmann Transformer

The Aristocraft manual for the locomotives indicates that it is recommended to use a pulse modulated transformer at 21 Volts. Since I was running 2 powered F units in A-A configuration I expected that the Bachmann transformer would be a bit under-powered. Accordingly, I figured that the problem was the small transformer and went about acquiring a more powerful one. I did a little research and decided on an original Aristocraft Power/Plus Train Pack 7000 that was rated for the correct voltage, used pulse modulation, and had much higher power rating of 60VA.

Aristocraft Power/Plus transformer. Phot shows set to 16V, but for F units, use 21V

This seemed to solve the problem, but after adding 5 passenger cars, the overload kicked in after about 10-15 minutes of running. I then decided to test the transformer with just the engines to be sure there was no inherent problem with the unit or the engines. I was able to run all three engines in A-B-A configuration without cars for 30 minutes with no problem. Adding cars back one at a time, I found the problem occurred after adding the 4th car. I found that a single engine would spin its wheels and not move when only three cars were attached. Obviously, this meant that the rolling resistance to the cars was excessive.

The first thing I did was to clean the wheels and lubricate all of the axles with graphite. This helped, and I could see the cars rolling more easily than before, but this did not eliminate the overload problem. My next thought was that the track radius was too tight for these cars. Since I have the original boxes and manuals for these cars, I was able to verify that the cars suitable to be run on Aristocraft Medium Curves (8 ft diameter) or larger. I had originally checked that and had used that track to assemble the suspended railway, so this did not appear to be the problem, or was it?

Aristocraft Medium Curved Track

That left me puzzled. So I spent some time closely observing the train in operation, looking to see where it might be struggling. I found that when the full train was attached, the engines struggled most when the engines were on the straight leg and the train extended around the end of the loop, where the train was essentially making a U-turn. This made it clear to me that while, the cars will operate on the Medium Curves, there is just too much resistance to pull a train around the U, given the length of the cars and the eccentricity of the tension through the couples. That leaves me with two options: 1. Run a different train of shorter cars; or 2. Change the track to a larger radius. (There is a third option I am exploring to shorten the wheelbase of the passenger cars, but that is a whole other project.)

So for now, I am running a Bachmann Denver & Rio Grande set on the suspended track. It runs fine with no issues. This makes the suspended trackway functional and fun, while I try to figure out what to do to make my big train run. I find this whole episode amusing, since I am always advising customers to use a track radius large enough to accommodate the longest locomotives and cars that they may want to use. I thought I had done that, following the manufacturers recommendation, but still had a radius issue. I guess the lesson is that the minimum is not always enough, and one should use the largest radius feasible in the space.

Here is a little video for your enjoyment.

This was a fun and interesting project, with a few surprises along the way. All model railroad projects will come across unexpected issues at some point. Most are minor and add interest to the work, but some are more substantial and require real thought and may change your plans. The secret is to not be put off by them, but to enjoy the process. I hope you enjoyed following along. This is now a part of the shop and brings the total to seven operating trains in the shop from N to G.

Happy Railroading

Mike