This whitemetal casting represents the standard Midland Railway signal lamp case of the Adlake long-burning type. Dimensions are approximately 8½mm high x 5½mm wide across the lenses. This pattern of lamp can also be used for parts of the Midland & Great Northern Joint, Great Central, and Lancashire & Yorkshire railway companies. It was also used on level crossing gates.
Post-grouping conversion of signals to upper quadrant arms normally saw replacement of the lamp with a more modern type (SC011 or SC025), as the lamp would have to move from the right to the left hand side of the post.