In the 1920s several railway appliance manufacturers offered mechanisms for multiplying the power applied by the brake chain that wound around the bottom of the vertical staff, thus providing additional braking power. The two whose names ended with "...co" were Gemco and Ureco (Union Railway Equipment Co.). I'd vote for Ureco.
Looked at it again, it's certainly not Ureco; the "co" bit was a guess; the initial "Sh" I'm almost 100% on... looking again, hmm. Was there anything like Shearer or Sheaver?
