I've found that light trains (like stock holiday train w/ 9v motor in engine) work OK with up to 1 brick per track segment, but that only works for trains less than 3 or 4 light cars long, and even then, it really struggles. This looks fine though.
Ok, enough rambling on now.
Neat use of the old Technic parts! If only they came in the current grey to match... What are you planning to use these for?