This page explains how Tim Hui (USATT# 88906)'s rating went from 1638 to 1641 at the Trolley Car TTC 2013 September held on - 22 Sep 2013. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.