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As the same number 8198 appears with all three references to Thomas Ross, it must be at least 99.9% certain that they are for the same man.
The Military Cross was instituted in December 1914 as a gallantry award for junior commissioned officers and warrant officers, but would not be available to sergeants. Sergeant-major is a warrant officer, CSM is WO class 2, Regimental Sergeant major a WO class 1 - a very important figure in an infantry battalion.
I suspect that the 'T/RSM' would have nothing to do with transport, but be a 'temporary' rank. If he was commissioned, this would be published in the London Gazette, so more searches there would be worthwhile.
However... CSMs and RSMs were sometimes referred to, informally, as 'major'.
Peninsula Barracks in Orford, Warrington was the South Lancashire Regiment's depot for many years, but all has been transferred under mergers and amalgamations to Fulwood Barracks, Preston, Lancs, where you might get more details.
This site will give you lots of information about the regiment and WW1 in general: <http://www.1914-1918.net/>. There is a linked Great War Forum.
A
[beaten to it by jds!]