British Waterways issued this earlier and I thought it worth sharing.
Mechanised Locks – Freight Waterways NE
Tuesday 27 March 2012 until further notice
There have recently been a number of incidents involving vessels passing red traffic lights at mechanised locks, these locks are used by large freight vessels. This notice provides general advice on lock traffic lights in the NE Waterways and is intended to reduce the likelihood of vessel collision at the locks.
LOCK LIGHT INSTRUCTION
Red Fixed Lock keeper in attendance – Do not enter lock. Wait for lights to change or contact lock keeper for advice
Red Flashing Lock keeper not in attendance – Flood conditions do not proceed. Red & Green Lock keeper in attendance – Self operation not possible at this time. Lock under preparation await further signal or instruction from lock keeper
Amber Lock keeper not in attendance – Lock set to self-operation. Leisure craft proceed with caution and self-operate the lock. Freight craft await instruction from lock keeper and do not enter lock unless instructed by the lock keeper.
Green Lock keeper in attendance – Enter lock & follow lock keepers instructions. Self-operation not available at this time.