Light Railways in the UK – the early years after the 1896 Act – The Railway Magazine, August 1905. …
A note in the August 1905 edition of The Railway Magazine mentions a 1904 report from the Light Railway Commissioners and comments from the Board of Trade in 1905.
The Regulation of Railways Act 1868 permitted the construction of light railways subject to '…such conditions and regulations as the Board of Trade may from time to time impose or make'; for such railways it specified a maximum permitted axle weight and stated that '…the regulations respecting the speed of trains shall not authorize a speed exceeding at any time twenty-five miles an hour'.
http://rogerfarnworth.com/2024/09/17/light-railways-in-the-uk-the-early-years-after-the-1896-act-the-railway-magazine-august-1905/"The Light Railways Act 1896 did not specify any exceptions or limitations that should apply to light railways; it did not even attempt to define a 'light railway'. However, it gave powers to a panel of three Light Railway Commissioners to include 'provisions for the safety of the public… as they think necessary for the proper construction and working of the railway' in any light railway order (LRO) granted under the act. These could limit vehicle axle weights and speeds: the maximum speed of 25 miles per hour (mph) often associated with the Light Railways Act 1896 is not specified in the act but was a product of the earlier Regulation of Railways Act 1868. … However, limits were particularly needed when lightly laid track and relatively modest bridges were used in order to keep costs down."
