A while back, I embarked on a construction project that has taken some time to develop and is in the final phase of completion. I had heard about the possibility of building a Speed Matching Circle that would automatically create the Speed Table for a locomotive based on a given maximum scale speed. Any locomotive that was run through this process would run beautifully with any other that this was done with. It can be built for any scale. I found that the Raleigh North Carolina Model Railroad club has modelers that built two such layouts and contacted one based on the information provided in his documentation: https://nrmrc.org/dcc/app-notes/dcc-locomotive-speed-matching. The system runs on a Jython script within the JMRI DecoderPro software. I am still sorting out some issues with the whole setup but hope to have it fully functional and portable soon. Attached are some pictures of the setup that I have built using some ash and oak plywood, a Digitrax Zephyr and BDL168 Block Detection board.
I got it up and operating completely within a half hour of the post. Anyone interested in building their own can contact me via Conversations or just follow this thread. There are some modifications and updates that I have made to the script.
The process of allowing the system to speed match a locomotive takes about 30 minutes - all hands-off; the computer and circle do all the work and then writes the speed table to the locomotive.
The pieces needed to build this system are as follows: For HO: 16 pieces of Kato Unitrack 21 5/8" radius curves - 4 each 2-210 16 pieces Kato Insulated Uni-Joiner - 1 each 24-816 (20 pieces) For N Scale: 16 pieces Kato Unitrack 19" radius curves - 4 each 20-160 16 pieces Kato Insulated Uni-Joiner - 1 each 24-816 (20 pieces) For both scales: 1 - Digitrax Zephyr DCS50 or DCS51 1 - Digitrax BDL168 Block Detector module 1 - Acculites #4001 BDL168 Breakout Board Multizone (acculites.com - this greatly simplifies connections to the BDL168) 1 - Locobuffer USB (rr-cirkits.com) 1 - power supply 15VDC 5A (the one that comes with the Digitrax Zephyr will work) 1 - half sheet of plywood (I used 1/4" oak for looks) cut in half 3 - 1"x3"x8' ash for vertical pieces 1 - 4' piano hinge plus screws 1 - pair suitcase latches 1 - door handle (for carrying) 1 - package wire tie anchors Commerical Electric #HW-4ACB (from Home Depot) 1 - package 4" wire ties Commercial Electric #GT-100MCB (from Home Depot) 1 - Cinch 2 position Barrier Strip 3 - Cinch 4 position Barrier Strips 1 - Cinch 8 position Barrier Strip 1 - Cinch 14 position Barrier Strip 1 - Cinch 20 position Barrier Strip 1 - 8 postion Barrier Strip Jumper to match barrier strips (to be cut into 2 - 2 position and 1 - 3 position jumpers) 22ga hookup wire 6 conductor flat wire phone cable and four RJ-11 6P6C connectors for connecting Loconet between Zephyr, Locobuffer USB and BDL168 3M Outdoor Mounting tape #411DC-SF (Home Depot) I used suspended ceiling hanger wire run through holes drilled in the road bed from side to side to hold down the track but allow it to be disconnected where the setup hinges apart. The hanger wire is anchored using wire tie anchor bases with clearance holes drilled through the slots. (Look at the pictures in post #1) The reason is wired as seen using all the barrier strips is because I wanted it portable and easy to break apart if diagnosis is necessary. I chose to use the inside rail of the curves as the individual blocks for detection. The rail joiners have to be removed for that rail and replaced with the insulated joiners. I drilled holes in the roadbed to accommodate the feeder wires for each track section. The feeders to the outside rails all connect together and are fed directly from one of the rail outputs from the Zephyr. The other rail connection of the Zephyr goes to the BDL168 wired in the Direct Home wiring like found on page 6 in the BDL168 manual. The individual segments of inner rail are connected to the BDL168 Zones A - D DS1 - DS16 outputs. These are the power feeds to the track that have the occupancy detection. Basically follow the BDL168 wiring diagram on page 6 of its manual. NOTE; with the individual lengths of the 16 blocks of HO Unitrack, it could be difficult to speed match long locomotives, i.e. steam locomotives or possibly SD40-2s, but steamers generally are not run in a consist. It will be necessary to combine adjacent sections of track to reduce the number of blocks to eight. That can be accomplished with more of the Barrier strip jumpers and some temporary re-wiring to the BDL168 Once you have all of the electrical connections made, it is time to install JMRI DecoderPro on your computer.
I recently put the Speed Matching Circle into operation and discovered that updates in either JMRI (Decoder Pro) and/or Java resulted in no operation. After spending the better part of a day with two friends remote in Ohio and Wisconsin, we got the Speed Matching Script updated and working with JMRI.4.20+Rc7ba8249b and Java 8 Update 201. The script is attached in Text (txt) format. To use it as a script, save the file as a .py file type instead of .txt.
I had recently wondered if something like this was possible. Good to know someone has done all the hard work for me already. Does the loop have to be that exact track for it to work, or could I substitute some 22" bachmann EZ track I have laying around? Also, can I use something other than a Zephyr for this operation? A few months ago I upgraded to the new EVOXD system Digitrax has out, would that work?
Any track that you can break up into blocks should work; just remember to insulate the gaps in the detection rail between blocks. Any Digitrax Command Station will work since the Locobuffer USB talks through the Loconet to the Command Station, however in the case of the new DCS210+ or DCS240 Command Stations, you could eliminate the Locobuffer USB because they both have USB ports.
