BTW, 3 Railking engines ( no smoke) should run fine on a single Z1000 pack. Unless it's not working correctly. I think it's the track wiring.
I feel that wire and connection point is only good for one engine.
I had gone over these types of issues before. I was having software problems when consists were made up of mixed PS2 with PS3 engines. It was suggested that my signal must be weak. It wasn't. I could run 6 PS3 engines without issues. My track wiring was also good. It never hurts to check stuff as we all can be wrong! A wire can fail, a connection, just about anything can go bad I've learned. We have to go over everything to find what is the weak link or fail point.
I use and suggest for others:
#14 multi strand wire. I've used speaker, low voltage outdoor lighting, and OGR cable with similar good results. It's soldered directly to Atlas 2 rail track in most spots. Some still have smaller short wires as jumpers.
Lionel PH180 bricks. I've used others and got good results including my Z4000 (currently on my 3 rail), Z1000, Z750, and Z500 bricks.
I have large Bridgewerks DC packs on my G scale using the #14 wire.
I removed my bulbs and filters after testing when using version L TIUs now. I still use them with my older TIU (upper 3 rail loop).
Each loop in my basement is divided into 4 blocks. I found that to work good for signal and power. I would divide more for largest consists with smoke on (more than 4-5 engine groups in each DP position) and larger layouts than mine.
