Differences between the Lionel 1015 & 1035 engines

Hi,

    I am trying to figure out the differences between the 1015 and 1035 engines.  I have a Winner Lines flyer from 1932 and it appears that the 1015 was stamped on the side of the cab, but in Doyle's book it appears that the photo does not have the 1015 stamped on it based on the description.  The 1035 seems to have a plain cab and based on the description in the Winner Lines flyer it also had a working light, but Doyle does not mention that at all.

    Thank you,

          Kevin Coyle