At the bottom of web page is collection of thumbnail photos of Latil Tar trucks. One image shows a 155 deBange being towed, with best view of the "avant train" that I have seen so far TRACTEUR LATIL TAR.
The drawings come from a multi-volume document on artillery officer education which is in the French archive gallica.bnf.fr. The original drawings are much better and not resized as these are.