THE SIGNAL BOX

LEVER FRAMES

BRITISH RAILWAY LEVER FRAMES

Stevens & Sons lever frames

Stevens & Sons Hook-locking lever frameStevens & Sons Hook-locking lever frame

This early lever frame appears to be a Stevens & Sons' Hook-locking frame which they manufactured over the 1860-1870 period. Locking was achieved by a range spring-loaded bars (with hooks to lock other levers) which were activated by the movement of each lever.

This type of frame was superseded when Stevens invented the now ubiquitous tappet locking.

The spring-loaded lever catches are not typical of S&S frames, a cast box worked by gravity is more common.

The lever badges comprising a small block for the lever number over a large block for the description were a common feature on S&S' London-built frames.

This example is preserved at the York Railway Museum.

Stevens & Sons Tappet locking frameStevens & Sons Tappet locking frame

Stevens & Sons were the pioneers of tappet interlocking, now used universally, and only relinquished the power of it by carelessly allowing the patent to lapse.

They introduced this type of frame around 1870, but its simplicity has ensured examples continued to be used up to modern times.

They could be found distributed around the Great Eastern, Great Northern, London & South Western (almost exclusively), Maryport & Carlisle, North Eastern, Somerset & Dorset and other companies.

Notable is the style of the quadrants. The levers stand vertical when normal, causing gravity to assist the pulling of levers. Early examples had variable length travel on the levers according to the function - evidence of modification of this can be seen on the accompanying illustration.

Most were manufactured with a lever spacing of 418", but could also be found at 518". The example shown here was built at 4" centres which was the standard specified by the Great Northern company.

This example is at Blotoft Sidings, more details of which can be found in the Photo Gallery. Similar frames are illustrated at Broad Street No.2 and Romsey.

Stevens & Sons Glasgow pattern lever frameStevens & Sons Glasgow Pattern lever frame

Stevens also had a Glasgow factory, but the frames they manufactured were not identical. Levers were spaced at 414" or 514" rather than the English 418" and 518" dimensions. Also, the lever handles only measured 9" in length rather than 12", creating a smaller lever.

Beneath floor level, there were also two types of construction leading to sub-types being identified as Old or New Pattern.

Glasgow Pattern frames were used almost exclusively by all Scottish companies apart from the Highland. This led to a continuing demand for the type through LNER/LMS and BR days and many were built by other contractors after the demise of the Stevens business.

This illustration shows Taynuilt, on which more details can be found in the Photo Gallery.

Stevens & Sons Glasgow pattern frame, of the G&SW variety.The Glasgow & South Western Railway built their own Old and New Pattern frames from the 1880s onwards. The New Pattern examples are easily distinguished by the presence of two catch guides per lever on the quadrants.

All GSW-built frames have the company's identity marked on the end castings.

This illustration is of Elderslie No.1.

Stevens & Sons Glasgow Pattern frame, manufactired by Railway Signal Company.This is one of the last batch of Glasgow Pattern frames, constructed in 1974 by the Railway Signal Company.

Notice how the design has remained the same for nearly 100 years, although modern luxuries such as the white plastic lever handle sleeves have been provided.

This illustration is of Huntly, on which more details can be found in the Photo Gallery. Similar frames are illustrated at Inverurie and Thornton Yard.

Stevens & Sons Ground FrameStevens & Sons Ground Frame

The Stevens company also designed a special frame for use at ground level. Although described as a "ground frame" this did not restrict its use to outside levers and it was used extensively in low or ground level signal boxes.

The quadrant plates were located about half way up the lever, making the levers themselves appear very short. The area below the quadrant plates was boxed in to protect the locking mechanism.

The presence of this raised portion gave this type of frame the nickname of "knee" frame, probably because signalmen kept banging their knees! This term has become so universal that these frames are rarely referred to as anything else.

English versions were manufactured at 458" spacing, but once again the Glasgow products differed and were made with 434" centres.

This illustration is of a Glasgow-built example at Dingwall North. An English example at Betchworth can be seen in the Photo Gallery

 

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