Smoother running conventionals

Additional lockons will solve the issue. You can start by placing one at that furthest point (where the slowdown is most pronounced) and run a power and ground wire from the transformer (use the same posts that you're using for the original lockon. 

On a large layout you can run as many additional lockons, from the same power source, as you need. Some of our temporary loops have used 4 lockons to keep the power level even.

I'll give it a shot. Thanks!

Yep, while the connections are "clean", the "good contact" may not be enough.  It's easy to check what's going on, just measure the voltage drop across several joints with an electrical load on the track past the lockon, you'll see the problem.