Attachment fitted to A4 60025 Falcon

[toyotaanthony]

Addmittedly it's concerning BR days, but there's an enquiring article & photo in the February copy of 'Steam World' of A4 class 60025 Falcon for the purpose of a certain 'attatchment'.
She's running light engine through Grantham to sidings at the south end of the station.
Quite prominently can be seen on the fireman's side a smallish square attatchment from a ''stem'' similar to what we relate nowadays to as a wing mirror. It is situated some three inches above the top forward corner of the Falcon nameplate with a small diameter pipe down and at right angles to enter the casing. It protrudes out about 6 + inches.
A historian acknowledges the fitment was added in June 1959, observed in place August 27th 1960, but not present September 16th 1960. The photo was taken July 21st 1960.
Are there any suggestions as to the purpose of this bracket?

[Blink Bonny]

She certainly had a smokebox vacuum gauge fitted in the '50s as part of the experimentation with the Kylchap gear but I understood that the bracket was removed along with the gauge. The gauge faced backwards and redings were taken that way. One presumes that the test people were selected on the basis of excellent eyesight.....

[Iron Duke]

A photograph showing this device fitted to 60025 Falcon has been added to the Tracks Through Grantham website.
You can see this image by visiting the page via this link http://www.tracksthroughgrantham.uk/rec ... -grantham/ and then scrolling down to the next to last image.