TN is an italian heritage machine, small cab, cab be had in orchard versions etc, available supersteer, low centre of gravity. Became the T4000. Roughly equivalent to a 400 or 4000 series MF in size. Open station is one step easy to get on/off, popular for beef operations, feeding, cleaning out.
TL is a Fiat heritage, but of Turkish origin I believe? It is heavier than a TN, has the big nice Ford/NH cab on it, not as low as the TN, no narrow model. Was the xx35 series before becoming TL. No supersteer axle. Became the T5000. Roughly equivalent size etc to JD/MF 500/5000 series.
TS is a NH heritage, made in UK I believe? Was the xx40 series before the TS. Could be spec'ed basic right up to the powershift transmission with ccls hydraulics. No supersteer axle. Heaviest machine out of the bunch, I think it has the strongest 3 point hitch and front axle. Tallest machine of the bunch too. Became the T6000, sort of. Roughly equivalent size etc to JD/MF 600/6000 series.