Appreciate the info on the Electromoke.
Looking at the pictures in one of the links, we used to use those relays to switch in the series field shunts on lifts with DC generators (Ward-Leonard) to alter the compounding for levelling. The loop contactor (main breaking contact for the lift motor) was much bigger, about 30mm square. Possibly too big to fit in there without extensive modification.
“I offer my opponents a bargain: if they will stop telling lies about us, I will stop telling the truth about them”