In these April 1963 pictures, we see two Perley Thomas cars, 906 and 922, apparently fresh from the paint shop, equipped with new round-cornered upper windows and doors.  They almost gleam in the sunlight.  Note how the upper windows of 906, above, have larger openings than those of 922, below.  Each car is stopped at the last stop before traversing the loop.  To our left in the second picture, we see another Canal car which still has square-cornered windows on the outbound track awaiting its next departure time.