A set of four Train Protection Warning System (TPWS) buffer stop grids. The fitting of full size TPWS grids to prevent collisions with buffers can be problematic due to the low speeds involved. From 2002 smaller grids have been installed in these situations to ensure correct performance.
These grids are designed to be fitted to Hornby track (or any other make of track in which the centre of the sleepers are 7mm apart).
Fitting of the Train Protection Warning System (TPWS) was mandated under railway safety regulations introduced in 1999. TPWS is primarily designed to prevent high speed head-on or side-on collisions. It does not help prevent rear-end collisions. Exact placement of the activation grids are dependent upon the speed limit imposed on the line. For full details see this detailed description