Forward
This dissertation may be of interest to DCS users who wish to improve the performance of their Subway or other Station-Stop trains. It is based on my experiences while tuning my two subways to provide a more reliable experience then when they came out of the box from MTH. I will tell everyone right off that this technology, while it is novel, entertaining and enjoyable will probably never be perfect. There are just too many variables. The following explainations should make valuable reading for Subway users, interesting for others technical curiousity and totally boring for others. You decide for yourself.
Background
I have owned an MTH R26 PS2 Lexington Ave subway for some time. I built an under the table two track end to end (out & back) system using DCS. Subway never performed well! It ran on Track 1 which is approximately 60’ long with two end stops and two interim stops. Track 2 is approximately 25’ long and has just two end stops. Track 2 went unused until recently I bought a used R17 Yankee Stadium RTR two car set to use on it. This set was even more unreliable. Both sets ran back & forth a couple of times before banging into bumpers and throwing rubber tires. At this point I decided to take on the challenge of finding out why!
Preparation for additional diagnosis.
I found MTH documentation on how to properly program these units under DCS pitifully inadequate. Only Barry’s book provided some additional insight as to how to proceed. After following all basic rules to insure optimum mechanics condition (tracks, lubrication, tires, tach tape etc.) and Barry’s programming instructions with no success, the frustration began to build. Performance was as before, and R17 eworse than the R26!
New Approach
I stripped both power units of cabs and wheel housings to allow for better visual observation. Focus was on (out & back) O&B operation, comparing performance of one subway unit to the other and I also made use of two remotes for programming which was also a suggestion in Barry’s book. Everything looking OK and with no luck so far, I decide to ask Ben Fioriello of the NJ Hi-railers for some advice since I know he has extensive Subway operation experience at the club. Besides our rehash of all the basics, he pointed me to take a hard look at the tach system which turned out to be an extremely interesting and valuable piece of advice.
Comparison Approach & Observations
I went directly to my tools and pulled out a Micrometer and set of feeler gauges. Counting the black stripes on the tach was amazing. The R26 had 24 but the first and last black stripes were practically together as one rather than equally spaced. The R17 only had 22! The Mic showed that each flywheel diameter was different, (27.1 and 27.5 mm) . I went to my PS2 upgrade kit parts bin which had sets of tach tapes and realized that the diameters should be 27.7, each with 24 equally spaced black stripes. Using some white tape strips cut from the MTH tach tape decals, I built up the diameters to 27.7and replaced with proper tapes. BINGO! They both operated closely the same, but unfortunately still no cigar! At this point I focused on the tach reader distance from the flywheel. After modifying the slot that keeps the reader in its holder so I could change the distance in & out, I quickly determined that .032” was the optimum spacing to program a stop at both ends (engines only) quite well. The R17 Yankee two car set with no interim stops on the out & back(O&B) was performing good enough for now, not perfect mind you, but good enough to run O&B many times before banging a bumper. As Barry mentions in his book some ‘creep’ is inherent to the initial design.
At this point focus went to theR36 and frustration started to build, seemingly because with the interim stops, the creep built up and still caused a problem fairly quickly during operation. Each O&B cost 3” on a round trip and a number of times back & forth were all I could do before resetting the train start position. Where to go from here? Both units still had this ‘normal’ creep, R26 worse than the R17 seemingly caused by the interim stops.
Two Remote Programming
At this point, I had convinced myself that if I were able to get away from the thumbwheel start and stop during programming and be more precise with start and stops, that I could get to the bottom of this. Another conversation with Ben put me onto using two remotes and the TMCC ‘quickspeed’ procedure with a second remote. This feature was new with DCS4.0. As a result, here is the procedure I developed.
Remote #1 to be used for setting the station stops only. Remote #2 to be used for controlling train speed and start stop.
First I set the R26 up jn this matter. 1) I Did an engine ‘feature reset’, 2) Set MAX speed at 20, 3) Set ACC speed at 1, 4) Set DEC speed at 25. 5) Added other 3 cars to the train.
Remote #1 was used to 1 )set DCS track voltage at 18V. 2) Power up the R26. 3) Set engine to ‘learn mode’using MTC & MLM soft keys. Then, used soft key LST to find the first station stop and then SAV once to save.
Remote #2 was then used to 1) follow ‘Quickspeed’ procedure to start engine moving to the first and following stops at 25 mph. 2) Halt the engine at a precise place at the first and following stops using the ‘direction ‘key.
Now back to remote #1 to find the next stop sound file and save it. Then back to Remote #2 to start and stop as before. Each ‘start &stop’ was precise and at the last stop I hit SAV twice to complete the programming. Now it was time to test results. After bringing back R26 to starting position, I restarted the engine, set it to AUTO mode (MTC & FAS) and was ready to go. I used the Quickspeed process to start up at max speed of 25 MPH (now using only one remote)and away the R26 went!
More Disappointment
There was some improvement, now losing only about 2” on each trip instead of 3”, not good enough! What I observed in this process was that during the programming cycle the train ‘start&stop’ procedure was instant and precise, but that during the ‘AUTO-MODE’ operation the stop was less precise and the slight creep was generated. The total sound file announcement (different tan in learn mode) would come on before the stop, the train would slow down to an ‘almost’ stop, creep forward a hair, then with a distinct ‘chirp’ sound from the sound file, the train would stop dead.
This got me thinking that the sound file which was generated during development and placed into the AUTO-STOP programming at some point calculated from tach tape reader results. Not sure why this would or could matter, I now focused on the sound file.
Sound File Download & a Degree of Success
Just for the heck of it, I loaded the R26 sound file with a replacement copy downloaded from the MTH website. I then went through the exact two remote LEARN MODE procedure conceived above and tested again. This time we had better success losing only around 1”(+/-)on an O&B trip. Since I left about a 6” slack ‘creep’ buffer at each end of the run, I could now run at least 10 O&B sessions before banging a bumper. This was good enough for me to use when demonstrating my subway system. I made no sound file change to the R17 as it had no interim stops and was more reliable. Watching two subways come and go is awesome. Who knows, maybe adding Doppler effect is next project.
Summary
1) Flywheels, tach strips and tach reader perfection and adjustment is all important.
2) Amost precise set up for programming stops also adds value to the final results. Two remotes, Quickset speed control and setting ACC, DEC and MAX speeds also helps.
3) Soundfiles and ‘start/stop’ programming controls and tach strips are all related to each other , start there.
Final words
Many thanks to the Barry Book instructions to get a head start on diagnosing the issue. Even more thanks to Ben Fioriello of the NJ Hi-railers who pointed me in the right direction to localize the issue. No doubt that many of the imprecise happenings on our layouts , lashups etc. could be fixed with detail analysis of the summary items.
Some day when I have more time, I will follow Dave Hikel’s instructions and make my own custom strips for R26. “Never give up the ship!”
Dave Hikel’s strip instructions can be found here.
http://sites.google.com/site/h...hing-ps2-conversions
