Tyer's Electric Train Tablet System

Tyer’s Electric Train Tablet System is a historical railway signalling system used on single-line tracks to prevent head-on collisions. It was invented by English engineer Edward Tyer in 1878, following a deadly accident at Thorpe in 1874.

The system relied on physical tokens called “tablets,” which were circular metal discs engraved with unique numbers. Each single-line section would have a tablet instrument at each end, electrically connected by a cable.

Heres how it worked:

When a train driver needed to enter a single-line section, they would request the tablet from the Station Master at the starting point.

The Station Master at the starting point would use the tablet instrument to check if the line was clear. If it was, they would electrically release a tablet from the instrument at their end, which would then be physically collected and given to the train driver.

The train driver would then proceed down the single-line section, carrying the tablet as their permission to be on the line.

Once the train reached the end of the section, the driver would hand the tablet to the station master.

The Station Master would then use their tablet instrument to electrically signal the starting point station, indicating that the line was clear again.

This system ensured that only one train could be on a single-line section at a time, preventing head-on collisions. It was widely used in Britain and other countries, including New Zealand, where it remained in operation until 1994.