Each box is a track segment and displays the signal at entry. Shown are the up and down lines (North is at top of page) from Reading station down to Basingstoke. Included for context are the junctions out towards Tilehurst and Theale. The focus is on fully tracking the local stopping train bouncing between Reading and Basingstoke, other destinations are marked eg platforms at the big stations. Green lines indicate points set to travel between blocks shown.
A train is represented by the 4 digit head code or train reporting number, currently these codes are replaced by images. Express trains are shown as cross country trains, the local stopping train is in GWR green, other stopping trains that don't come to Bramley (like the Newbury train) get shown in blue. Freight trains look a bit like a train of containers
Generally the crossing goes down when a train is 3 blocks or about 3 minutes away from the crossing. A train 2-3 blocks behind a train approaching the crossing will generally mean the crossing stays down for that one to pass too.
Predictions are hard - the crossing activation appears to be down to individual signallers - some days you'll see the crossing go down earlier or later than usual
If you have questions - feel free to contact me and I can update this page