THE SIGNAL BOX

OVERSEAS

MECHANICAL LEVER FRAMES
Belgian State Railways (SNCB)

by John Hinson

Saxny lever frame in Belgium
Photograph from the collection of Dr J W F Scrimgeour

With John Saxby (of the British firm Saxby & Farmer) establishing himself in Paris, it isn't surprising that many of the mechanical frames in Belgium were of Saxby's rocker type. In these, the rockers (seen between the lever quadrants) were driven by the operation of the catch handle of the lever, and transmitted the action to the horizontally placed locking rods behind the frame, which can be seen clearly in this view.

One interesting feature of the frame in this view is the provision of shields over the rockers to prevent their being stood on. In the UK, signalmen used to appreciate being able to operate the catch handle by stepping on the rocker but their was an inherent risk in that if this was done accidentally a points lever could spring out of the frame and derail a train.

Frames of this type were installed in signal boxes in Belgium up to around 1900.

The signal box itself (which has not been identified) seems likely to have also been built by Saxby, as it features the curved tops to the windows and a row of small windows above in similar style to the Saxby & Farmer box design of 1876.

Double-wire frame in Belgium
Photograph from the collection of Dr J W F Scrimgeour

Not all mechanical signalling in Belgium employed British-style lever frames; the double-wire system was also popular and this example shows a large double-wire lever frame. This type was manufactured by Siemens & Hlaske, and was adopted for new most work from 1900. These frames were used in both mechanical and electro-mechanical form and are identical to the standar frame used in Holland.

Towards the right-hand end of the frame, a bank of Siemens block instruments can also be seen.

Hybrid Saxby and double-wire frame
Photograph from the collection of Dr J W F Scrimgeour

This interesting view shows a rare hybrid arrangement of Saxby and double-wire frames. Many of the levers of the original Saxby frame have been removed, and a small bank of double-wire levers has been substituted centrally in the length of the frame. It was also possible to convert conventional levers to double-wire operation, and those remaining in use may have been so converted.

The interlocking is between the two frames is not the typical Semens & Halske type but by rods and cranks immediately behind the levers linking to the Saxby locking.

The boxes to the left are electric route locks, which were released by the train engaging a treadle after passing the relevant pointwork. Theywere an alternative to the provision of Facing Point Locks, and were operated by lifting up the large grip on the vertical member while pushing in the top plunger.

Additional notes by Michiel Rademakers



Comments about this article should be addressed to John Hinson