The Siemens train seats are notorious for showing the dirt.
At one stage a multi-coloured design similar to the Comeng fleet seats was tried, but now Metro have introduced a new design which is supposedly more vandalproof (and uses their corporate design, not Connex’s).
It’s on one 3-car Siemens set so far (for the gunzels, it’s 831M-2566T-832M).
Intriguingly, as some on Facebook noted, stations that don’t get electric trains such as Rockbank and Somerville have been included in the station names shown in the design. (Somerville at least gets the Stony Point trains, which is strictly speaking a Metro service, even though it’s run using V/Line sprinters. Rockbank only gets V/Line Ballarat line trains.)
But anyway, hopefully this new design will do a better job of staying clean and hiding the dirt.
This is the kind of thing PTV and/or Metro really should promote a bit more, to let people know they’re actually acknowledging the problem, and to gather feedback.