Original captions and text:  "Fig: 18. Gillingham &amp; Winans' "Crab" Locomotive" "Fig. 18 is copied from a photograph taken after the engine had been in service for many years." (Forney) "Fig. 8.  A Crab" (Bell).  This locomotive substantially conforms to the drawings in Winans' US Patent 308, granted in 1837.
anonymous (neither source cites an author).
J. Snowden Bell, <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dlpAAAAAIAAJ&amp;pg=PA29">The Early Motive Power of the Baltimore and Ohio Railroad</a>, Sinclair, New York, 1912; Fig. 8, page 29.  <a href="https://en.wikipedia.org/wiki/Matthias_N._Forney" class="extiw" title="w:Matthias N. Forney">Matthias N. Forney</a>, Reminiscences of Half a Century <a rel="nofollow" class="external text" href="https://books.google.com/books?id=BAXST_5aCssC&amp;pg=PA334">Proceedings of the New York Railroad Club</a>, Vol. XII, No. 7 (May 15, 1902); Fig. 18, page 334.