Railway stations in Lombardy are managed part by RFI (Italian Railway Network) and partly by Ferrovienord. To facilitate the use by travelers with disabilities and reduced mobility, both companies are making gradual structural and technological improvements on existing stations. 
In addition, in accordance with national and European standards, all new stations are designed and built from the beginning according to the accessibility standards for people with disabilities.

For RFI, you can consult on line information on services and facilities for accessibility in 630 major stations of the national network, which also included the 80 major stations of Lombardy: www.rfi.it

For Ferrovienord the accessibility and usability of the network stations (Milan branch and Iseo branch) are available at:www.ferrovienord.it

On Trenord website you can also check a list with the names of all the stations managed by RFI and by Ferrovienord in Lombardy.
In this list is specified when the access to the rails can take place autonomously and when instead of the service staff assistance is needed.

In case of doubts about the accessibility of stations you should always contact the assistance services for passengers with reduced mobility.