When Colchester was resgnalled a couple of years back, there was an article in the local paper saying that one of the crossings, at certain times of the day, could be 'down' 52 mins out of every hour.
Was that Chitts Hill? I know they replaced the manual gates with barriers recently (i.e. in the last year or two), not sure whether that would enable them to raise the barriers between trains, as I recall that was possible at Manningtree when they replaced the manual gates about 30 years ago.
The most trains I've ever waited for at a crossing was 5 at Ardleigh. But I don't think that that part of the GEML is that busy.