IF YOU want to get off the train at Swale, you have to tell the guard in good time. Otherwise the train goes straight through.

I alighted at a bleak and empty railway platform. Fifty yards away flowed the Swale channel. If the tide was high and ships were on the move, I would see the Kingsferry Bridge rise to let them pass through the narrow channel into the Medway.

The bridge sticks up out of the Kent marshes. It carries articulated lorries on their way to the docks and industrial estates on the Isle of Sheppey; the single track railway crosses it, too. Opened in 1960, it is the only bridge to Sheppey. Hauled by giant cables, the centre section rises vertically on four concrete towers to let ships pass. It can be seen from miles away.

The tide was low. I saw no ships. 'Come back tomorrow,' said three boatmen drinking tea in a shed by the sea wall. Another train clicked past. The procession of lorries continued. I crossed the bridge. A working light was on in the control room. I pressed a doorbell, and after a while the bridgemaster opened the door, by an inch. 'Have you got any ships coming through later today or maybe tonight?' I asked. 'I don't know, mate,' he replied grimly, and closed the door.

Kingsferry Bridge is at Ordnance Survey grid reference TQ914693

(Photograph omitted)