Need K-Line Shay Diagram

I've never seen that wiring diagram, it may be hard to come by.  I believe that the tach output to the RS boards may actually come from the speed control board.  I have a K-Line tank engine with the Cruise Commander M installed, and it needed a magnet and reed switch for the chuff after removing the K-Line cruise board.  If you want chuffing smoke, you'll also have to add a circuit to isolate the smoke motor drive.  I needed to do this recently and just cobbled together the little circuit below to do the job.  I tapped the 5V off the smoke unit to power it.  The transistors are 2N2222A, they were what was handy in my parts box.   The 100 ohm resistor was to bring the motor to a stop quicker, it's optional.

Your best bet may be to trace wire and write your own document as you disassemble.  I don't think you will get a diagram.  Sometime you can use the part numbers off the board if they are Lionel, cross it to an engine via the Lionel Parts sight, then possibly locate a Lionel Diagram off the service manual sight.

If his is a Lionel TMCC system, many of the functions on the Mother boards are generic and you just need to identify what each jumper connection does.  Antenna, rear coupler, head light, volume pot, speaker, motor drive, etc....   G

Just finished tracing out the wiring. What a mess. But I have figured it out. The chuff sound is indeed derived from the motor tach. The tach signal goes to the motor drive board which I have to replaced since it has a factory programming defect. The new board will not use the tach for feedback since it gets the speed signal from motor back emf. It takes 4 turns of the flywheel to make a chuff. Some where on the motor drive board a divide by N occurs to the tach pulse train. I have yet to determine how many pulses per revolution the signal is. The chuff output comes off of the board and goes to the chuff input pin on the R2LC which then combines it with the serial data going to the sound board. I think I can use a small Arduino and have it do a divide by N from and input pin and send to an output pin and send that to the sound board chuff input since I will be replacing every board in the loco. So I think I have a plan. 

Well, for sure an Arduino wouldn't be taxed to provide a divide by N signal!   While you're doing a custom processor program, consider controlling the chuff of the fan in software as well from a separate pin.  That way, when the locomotive stops, after a couple of seconds you could run the fan at low speed to have smoke drifting from the stack at idle.  If you really want to get fancy, you could also reduce the power to the smoke resistor as well at idle.

Another cool upgrade would be the three step smoke level that the Lionel smoke regulator gives you, pretty easy once you have your own processor in the mix.

Jim, Not sure what your programming issue is , but there are some post on the forum that talked about how to reset K-line boards and program specific speed control for K-Lines speed control motor driver.  That may solve your issue.  G

Unless you can lead me to the exact post about reprogramming K-Line boards I cannot find it. Search returns nothing at all. The microprocessor on the K-Line specific board does not respond to the TMCC command to "set speed to value X"  It only responds to speed up one step, speed down one step, and direction commands. This is not uncommon as I had some Digital Dynamics Boards that had the same problem  and some TAS boards also. I replaced them all with ERR boards and problem went away. The reason for this is that the CAB1 only sends speed up and down commands. I am using JMRI iPhone throttles and it only sends "go to speed X" commands. 

Like the idea about the pulsing of the smoke generator. I could send a PWM command out of the Arduino that varied with speed and chuff. Might be fun to try. The smoke generator in the Shay is a simple 2 wire device. Need to investigate it further and see what its capabilities are.