Older Spectrum

While Bachmann is making newer stuff that is decent, they still do many non-standard and screwy things. Look up the numerous web posts about this sort of thing. The older split frame stuff is going to be a challenge. Wait until you pull apart the frame and the plastic on the motor sticks to the frame, effectively destroying that original motor. You'll love that experience!

I could tell you A LOT of boring stories about my experiences. Instead, I will just say that any of my Bachmann projects will be totally disassembled and have just about every piece of original wiring removed, it takes more effort, but it will be worth it.

Two for One Bachmanns

I had several K4's all of which came DCC ready, so you may be surprised to find that yours are also. I found the reliability of the K4s to be poor to depressing and ended up buying "bad" or "for parts only" units on ebay for replacement parts. Problems included weird, non-standard wiring colors, out of gauge wheels, bad solder joints, broken connectors, poor assembly (mostly stripped screws) and more. You can download an assembly drawing at HO K4 4-6-2 PACIFIC DCC SOUND. As with many other Bachmann engines I found that I needed two (or more in the case of their Shays) to assemble one reliable engine, but once rebuilt they ran reasonably well and pulled fairly well.

K4

Check the TCS decoder site. I saw the page some time ago. Make sure pickups are clean. A lot of weight. Some say they pull well. Adding metal wheels and pickups plus wires to tenders could help. Use Kadee clips from couplers.
You can put sound in the tender. Plenty of room. Get a six wire connector or the two connector assemblies from Bachmann. I did that with a different system some years ago. A two pin and a four pin connector. I just looked at the Bachmann diagrams for their locos as I have some of their locos.

http://tcsdcc.com/index.php/installation/ho-scale/bachmann-spectrum-k4-pacific-4-6-2/m1

Bachmann now sells the K4 with the WOW sound.

Rich

K4

Thanks for the info.  I will do some more research.  I got the K4 really cheap, so I will see if it is worth the effort.