Subject: Bradford C.T. trolleybus detail
Chassis: AEC 661T
Body: English Electric H30/26R
Location: Preston, Dick, Kerr works
Date: 1938/39

The 'Regens' had featured roof-mounted circuit breakers which proved troublesome in service. Later vehicles moved to this more conventional position which is presumably why they were photographed. For the technically-minded these are English Electric Type D form C breakers.

The other item on the roof is a radio interference suppression unit, labelled a "Dubilier Anti-Interference Unit" and made by the Dubilier Condenser Co. (1925) Ltd. Mica capacitors were invented by William Dubilier in 1909.

Photograph from the GEC archive