This is my favourite trolley line in Toronto. I pretty much only ever take it westbound from Broadview and Gerrard so I don't have the same polkaroo experience with the ghost of the 504 that others describe.
Specific 504 win:
Last week I was at Mystic Muffin for lunch and when I left a 504 was at the corner. The opposite corner from where I was at. He was stalled at a red light and I hurried across the street but I had to do a double cross and his light was about to turn green. With worry on my face I impatiently waited for the walk sign and prepared myself for the pending devastation of the trolley pulling away just as I arrived at the stop. But he waited for me. I could not believe it. The driver waited for me. He preserved the happiness I had been working on that day.
504 forever.