[Scuderia_Turini]

Well my original photograph was correct, just not clearly identified so below is a better version. 
The right rail is fed with the Positive voltage supply and the left rail is fed via the controlled Negative supply. 
If you do not want dynamic braking then just using the two wire connections as Andy mentioned is the way to go.
I just refreshed my memory by checking a thread on the old Forum which reached a succesfull conclusion. As mentioned I will do a trial in the next couple of days and feed back here.

I have to say that the electronics for these units are a bit fragile so any modification needs a bit of care and carries a risk element of killing the unit, so its at your own risk...

The old thread suggests disconnecting the power feed from the Chrono unit and simply using a standard Scalextric powerbase (or the wiring from it) and that makes sense in some respects.  The Chrono unit only provides power to the rails when the timing is running so as to provide a "cold start" thereby preventing any jump starts. That feature can be annoying so worth thinking about.

Leo

Linky to the old place