You may try acrylics... I used that rustoleum on the bulk of my layout, did a little bit of track changes down the line and painted the rest with Vallejo acrylic dark umber (iirc). A very close match, and after I apply rust tones via pan pastel it gets even less noticeable. Not sure how the Vallejo will hold up long term, so far haven’t had any come off while ballasting and detailing etc.