A brief investigation suggests the discrepancy is due to the rail position.


Diff - Rail
0.00 true
0.19 +4
0.43 +8

The sportscolour 600m time seems to exceed the AJC time by ~:

5% of rail position.

The AJC time appears to be correct.

Sportscolour uses underground sensors and obviously it wouldn't dig them up and reposition every time the rail moves. It claims to normalise the times to 200m but apparently doesn't bother to here.

It's not a big deal to remember than when the rail is out 8m the 600m trench is really ~607m, then scale the observed time by 600/607.

Still this sloppy status quo should give false rail runners tremendous early speed figures for experts to enthuse about.