View single post by Craig W
 Posted: Sun Aug 25th, 2013 06:01 am
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Craig W

Joined: Sat Jan 5th, 2013
Location: Napa, California USA
Posts: 71
For now, R/C conversions can take a bit of work, but are absolutely feasible for most modelers who are willing to learn a bit about the systems and aren't afraid of a little hand work and some soldering.

Lately, my experiments have focused on track powered R/C control and I recently had the chance to test DCC against Track powered R/C back to back, on my local club layout. I found the results to be surprising.

The locomotives I used for the test were an NCE DCC equipped, Atlas Dash 8-40B and an Athearn GP-50, using an Orange R/C receiver with a home made ESC (electronic speed control) using a home spun H-bridge for reverse with some el-cheapo Radio shack power filtering, via some caps and a rectifier bridge. Total cost for the R/C package was a little over $30 in parts. I managed to stuff all of this junk into the stock GP, by cutting out an internal wall which is hidden directly below the dynamic brake fan. I added a brass platform for some of the extra components over the rear truck and made a similar weight for the front.

When I showed up at the club layout; neither locomotive had been tested and the DCC equipped loco required programming, which was gracefully handled by a fellow club member in about 10 minutes. The track at the club is cleaned at regular intervals, but as I found out, still had some problem areas which affected both R/C and DCC systems. Track power on my home layout and test rack is well filtered and I have never had issues using it with R/C, but the club layout was a different environment and I wondered if the rectifier and caps I used were up to the task.

I put the GP-50 on the rails first, only to find out that the singe 400uF cap and 2A rectifier made for a bad combo on the DCC layout. It left the loco stalled and buzzing, although it had worked flawlessly on my home set-up.

After replacing the rectifier and exchanging the 400uF cap for 2 smaller 100uF caps, I was ready for another try. This time I was off and running. I had expected a higher top speed for the GP, but it only managed a scale 70 MPH pulling 3 cars at max throttle, which was fine by me, since I don’t run my trains like slot cars, but still puzzling.

Performance was very smooth overall, but starting was noticeably affected as was speed stability on the monster club layout. The club layout is packed full of boosters for the DCC system, but my impression of the system, is that it may actually need more. After 10 minutes of constant travel, I hit my first section of dead rail and the GP-50 came to a halt. With a gentle push it was up and running for another 5 until hitting a second dead spot, which reminded me of why I decided to go with R/C in the first place. After 20 minutes of run time I felt that the R/C system had proven itself to be viable. I range tested the system from every place in the building and had perfect communication. The system is still missing the one item that would make it just about perfect; Batteries!

I honestly expected the DCC equipped Atlas engine to out pull and outrun the R/C loco by leaps and bounds, but much to my surprise, I found it to be way more sensitive to dirty track and had to push it through quite a few areas. You could see it slowing down noticeably at certain points between DCC boosters as well. At slow speeds control was good but at the lowest speed setting, the R/C loco had a much more impressive range and overall had better speed stability. All of this went against my own intuition. Having run both locomotives on straight DC, you could easily tell that the Atlas loco was far superior to the Athearn.

By no means was this a scientific test, but I think my observations are note worthy. What did I learn here?

Not much that I didn’t all ready know, but good voltage filtering is essential with DCC track power. I’m now running (3) 100uF caps.

Out of the box Athearn locomotives work fairly well with cheap R/C gear.

Batteries are a very good thing for R/C locomotives. Yes Woodie, you did say so!

Below is a picture of the GP-50 chassis with the front weight and shell removed. Another board sits next to it, waiting to go into the Dash 8-40b for the next test. At the bottom of the picture you can see one of David T's micro sized marvels, the DT/RC RX61-1, which is still undergoing some tests, but looks very promising!

Last edited on Sun Aug 25th, 2013 06:50 am by Craig W

Model train enthusiast, Mechanical engineer, frequently misunderstood. :)
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