The alignment of railway tracks may be monitored using an accelerometer
(36) mounted on a bogie (24) of a railway vehicle to detect lateral
accelerations, and a displacement transducer (38) to monitor the lateral
displacements of a wheelset (27) relative to the bogie. The acceleration
signals are digitised, and processed corresponding to double integration,
so as to deduce the lateral displacements of the bogie, and in
conjunction with the signals from the displacement transducer hence to
determine the effective lateral displacements of the track. This can
provide a more useful indication of the lateral positions of the rails
than measurements of the gauge faces. Such equipment (16) may be
installed in a service vehicle, and operate automatically, downloading
resulting data to a remote base station at regular intervals.