The Secret Tunnels of South Heighton

The Battery Room.  Before & After 2000.

These pictures show the Battery room as found in 1994, and after clean-up by the Friends of HMS Forward.

The Battery room accommodated the batteries for the PMBX1A (Private Manual Branch Exchange) telephone equipment. This would have comprised strong wooden racks for banks of main and stand-by secondary cells to work the switchboards.  There would have been the associated rectifiers, switching and regulating equipment, and the odd carboy of distilled water. There would also have been one or more separate banks of batteries for the emergency lights in the Operational Area as a precaution against failure of the public electricity supply AND the stand-by engine.

Such a scenario might have arisen if the enemy had landed and destroyed the public electricity distribution, and also discovered and blocked the stand-by engine exhaust. In this situation there would have been a need for lighting in the tunnel whilst all the code books, Typex cipher machinery, archived messages, radio equipment, telephone equipment, and other militarily sensitive material was destroyed or burned against capture.

The three-phase public electricity supply entered this chamber through a 3 ins (75 mm) pipe (just visible centre rear at high level) and terminated on the four-bar distribution box seen at the far end of the right picture. I recall it was mounted on the far wall in more or less this position. The lack of paint on the lower part of the right wall suggests the presence of an obstacle along this wall. Viewed from the opposite direction there is even more compelling evidence of some sort of bench or equipment that obstructed the paint brush. There is also a floor duct, not apparent in the first pictures, running along the bottom of the wall and under the breeze block partition. This was the route taken by the power cable between the aforementioned distribution box and the power frame in the air conditioning room. The large square 'hole' in the breeze block partition was a perforated-zinc ventilation 'window'.  

One most noticeable point is the reduction in humidity due to the removal of decaying rubbish strewn all over the floors which, as can be seen, are dust-dry now even with the minimal amount of air flow that reaches here.


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All illustrations and text on this site are 1941-2021 Geoffrey Ellis, or The Friends of HMS Forward, or Nick Catford.