Did Robert Lincoln Ride the Funeral Train to Baltimore?

[STS Lincolnite]

Who knows on which wall in the Lincoln Tomb exactly is this stone (RTL's cenotaph) ?

Robert's Cenotaph is on the same wall as the markers of Mary, Eddy & Willie, and Tad (these markers are listed from left to right when facing). The family members that are interred at the tomb are in a sort of chamber along with the marker for AL. On either side of the chamber there are gates that extend to be locked up and that retract to allow visitors through. Robert's cenotaph, when facing the markers for the Mary, Eddy & Willie, and Tad and with back toward AL's marker, is to the right of Tad and just outside the lockable gate (whereas the others are between the lockable gates).