Considering our system is comprised of multi-modal options, all on a single fare (heavy rail, subways, RT, streetcars, busses, etc.), I don't really think there is a logical way to brand them outside of just using numbers (ie. there's only 2 dimensions to alphanumeric, but we have many more modes). What I do agree with however, is that I think there needs to be a clearer distinction between what constitutes LRT and streetcar. 500-series lines can be grade-separated, right of way, in traffic and underground, but Line 5 and 6 also follow these rules.