Transit Revitalization And Infrastructure Needs Act or the TRAIN Act This bill expands the authority of the Department of Transportation (DOT) to provide fixed guideway capital investment grants. DOT may provide grants to state and local governments to assist in (1) expanding transit station platforms, (2) increasing service frequency, (3) increasing the capacity of an existing station, and (4) replacing temporary measures (including the use of rail equipment) which have been used to expand system capacity. A fixed guideway capital investment grant project may advance to the engineering phase of development if DOT makes certain determinations, including (1) that the project will increase capacity of an existing fixed guideway system, corridor, or station at least 10% or replace temporary measures; and (2) whether existing fixed guideway transit vehicles or stations are at or over capacity, or are projected to be at or over capacity within the next 10 years.