About a month ago, I wrote about the 71, one of the two bus routes in Boston that use electric trolleybuses. The 73 is the other one of the two. Well, not anymore. The trolleybuses are being retired as of today. :(
The 73 is pretty similar to the 71. The 73 starts in the Harvard busway and proceeds west along Mount Auburn St. The 73 splits from the 71 at Belmont St and continues along to Waverley station on the Fitchburg Line. Waverley is a smaller Commuter Rail station. I haven't wrote about it yet, so I'll save whatever rant I may have for then. It is in Zone 1, so the 73 can be used to get a cheaper fare into downtown Boston and beyond if you're coming from the Fitchburg Line.
I'm going to guess that this is a fairly popular route. It's one of the few routes that serve Belmont, the others being the 74 and 75 from Harvard to Belmont station, the 78 from Harvard to Arlmont Village in Arlington (passes through a portion of Belmont), and the 554 from Waltham to Waverley.
Also, this route's schedule runs for a large portion of the day. The first trip on weekdays and Saturdays leaves Harvard at 4:45 am, and the first return trip from Waverley at 5:05 am. Trips start later on Sundays, at 6:37 am from both Harvard and Waverley. On all nights, the route runs regularly until about 1:30 am. The route runs frequently, with buses coming every 20 minutes at all times.
Overall, the 73 is a very good route. For a more suburban town, the 73 is a very good example of how a suburban bus route should be planned. Frequent, but not too frequent, service running throughout the whole day. This route also connects to other routes at Harvard, one of the major bus hubs on the MBTA system.