I have had to wait a fair while at several level crossings over the years, but taking a trip to London this weekend with my folding bike I found one that beat them all. I took a train to Mortlake and then had to cycle south, crossing the level crossing, and later had to return that way (though not to catch the train). Sadly I didn't actually time my waits, but I'm sure the wait from exiting the station was well in excess of ten minutes, and 5 trains crossed during that period. When I returned a few hours later. as I cycled along Mortlake High Street there was a long queue of vehicles waiting, and I thought to myself "That's good, I won't have to wait that long this time." How wrong I was. The wait was at least as long as the wait in the morning, and several of the people waiting around me were getting extremely frustrated judging by their calls on their phones they were having. There seemed to be a gap of well over 5 minutes (it felt like about ten) when no train passed by, and people just couldn't understand why the crossing didn't open.

Yes this crossing, and others I have had to wait at for several minutes, had footbridges alongside, but they are always very steeply graded steps, of no use at all to those with mobility issues or heavy luggage or cannot manage their bike and luggage up steps that steep. On the return journey, I noticed that several pedestrians and some cyclists, who had been waiting longer than me, eventually gave up waiting and tried the footbridge route, not all with success.

So I wondered which crossings people have found themselves having to wait for the longest times. Before this experience, my longest have been when visiting Lincoln, and using the crossing immediately west of the station. I also travel to Shoreham-by-Sea a lot and that can involve long waits at the crossing next to the station, though on average it isn't usually too bad.

Both were on Saturday afternoon, probably about 2.30pm and then about 4.30pm.

Barriers (well, certainly most of them) that are locally or CCTV^▸ (Closed Circuit TeleVision) supervised in track-circuited areas are default-set to auto raise as soon as the circuit over the level crossing goes clear.  Obviously that doesn't happen if the barriers are down for a train passing over the crossing on another line

Some crossing keepers/signalmen used to switch off this setting so that their action would initiate the raising of the barriers.  They were either bloody minded antagonistic people, or they had too much time on their hands

If you have Train 1 on the Down Main, Train 2 on the Up Main, and Train 3 on the Down:

Barriers dropped, say two minutes before Train 1 arrives at the crossing, so the driver gets greens on the approach.  The first signal that could give a yellow could be 1,800m or so in rear of the crossing, and you don't want the driver to see that as yellow as the train approaches, you want the driver to see a green. At a line speed of 80mph, say, you really do need to start those barriers dropping two minutes before the train gets there.  There will probably be an annunciator in the signalbox, to give awareness that the train is approaching, at a certain distance in rear of the crossing - a track circuit or a treadle

Say it's 2 minutes 20 seconds before Train 1 has cleared the crossing.  By which time, Train 2 could be within three minutes of arrival.  You wont lift the barriers to drop them again in less than a minute.  So they stay down.

Train 2 clears the crossing 5 minutes 40 seconds after the barriers were dropped.  And now Train 3 is about, following  maybe four minutes behind Train 1 on the Down, and not much more than three minutes from the crossing.  Again, you don't want to lift the barriers.  Train 3 arrives at the crossing 8 minutes or more after the barriers were first dropped

This is a general explanation, not specific to Stoke Canon Crossing. It works for two-aspect signals.   But it does give you an idea of why you'd have to wait there for a while, sometimes.  With three aspect signals, when you wouldn't want to show the driver a double yellow even further in rear of the crossing, the barriers may need to be dropped earlier.  Just admire the Saxby and Farmer built signalbox.  A listed building, I believe, and disused for around 40 years now