In this symbol, a small pack is placed on a track, giving us the noun trade route.
Illustrative Text Reference:
Harappa: Seal: H-1711 A (There is no view a): Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 239: New material, untraced
objects, and collections outside India and Pakistan: Suomalainen Tiedeakatemia.
The existence of this symbol suggests that such routes may have been actively maintained to ensure that they could be used by pack animals.