I have visited the lovely walled city of Lucca many times since the mid 90s for holidays. The rail network around Lucca feels like home territory- in fact, the reason I have a love of Italian trains is that the first time I walked into an Italian railway station was Lucca. The first thing I saw after walking out of the ticket office was a massive, brown E636 simmering. This loco blew me away and I have been an FS fan ever since.
During a recent visit, I took some video of the local lines. Here is my video of the 24km Pisa-Lucca route.
This line is old- parts of it opened just before the unification of Italy in 1846. It arrived in Pisa before the Pisa-Genova line and had a temporary station just outside the time until it could link in to Pisa Centrale.
The section between Centrale and S. Rossore is interesting- in the late 2000s, an additional track was built, so that Lucca trains could run without disrupting the main line. S. Rossore was already quite a strange station, as it is in a triangular formation with the station building on the third side of the triangle. However, it is even more strange now, as the old Lucca tracks have been embedded in asphalt, with a new platform being built to the side of these. I think the original strange arrangement was that the station was used by Italian Royalty, so they built a large building and space to transfer because of this.
Just after S Rossore is the only place where you can glimpse the famous Learning Tower.
The line is single track from S Rossore, with passing places at all stations except Ripfratta, where the loop has been removed.
At Bivio Montuolo, the line from Viareggio joins. This was built around 50 years after the Pisa line and results in an unusual operational arrngement. From the Montuolo to Lucca, the lines run parallel, and are treated as two bi-directional single lines. There is a junction at Montuolo, so trains can run in either direction on either line. Sometimes, two trains will head in the same direction next to each other. On this video, my train transfers to the "wrong" Viareggio line at Montuolo, as it needs to access the western bay platforms at Lucca. It is also possible to do this closer to Lucca, but if a train to Pisa is leaving Lucca, it makes sense to transfer early. So, often you will find the section is used as "quasi double track" for Pisa trains, but Viareggio trains tend to stick to their single track.
Trains on the line include "Jazz", "Rock" and E464/Vivalto coaches (all electric). Some services are run by diesel "Swing" units in order to position trains for the unelectrified Lucca-Aulla branch.
On this visit, there was no sign of Aln668 or 663s, or anything in XMPR colours (other than the E345 diesel on yard shunting duties). I think an Aln663 still pops up sometimes to help out on the Aulla branch.

Index Points
00:00:00 ETR324 4-car "Jazz" unit at Pisa Centrale
00:00:33 Leaving Pisa Centrale on ETR425 "Jazz"- service R18593 Pisa-Lucca
00:00:54 PisMover airport transit and Leopoldo line to Livorno leaves through the undergrowth
00:01:20 Goods avoiding line that allows direct access to Livorno, bypassing Pisa
00:01:37 Fiume Arno
00:02:48 Pisa S. Rossore
00:04:36 Line becomes single track- goods link from Genova direction joins behind the train
00:04:47 You can glimpse the learning tower of Pisa from here!
00:07:26 Line runs straight on the flat plain behind Pisa. 300m peaks can be seen.
00:08:22 Monte Castellare
00:09:16 S. Giuliano Terme
00:10:37 Monte S. Giuliano, then Monte Cupola in the background
00:11:40 The peak Le Cimette is behind Rigoli, with further higher peaks behind that
00:12:11 Rigoli (pass)
00:12:29 The line curves around a set of 400m peaks until the old Montuolo station
00:14:14 Old A11 passed over on the part demolished bridge
00:14:27 Ripafratta
00:14:43 Running by the Ozzeri channel, with the Serchio river on the other side of the bank
00:15:33 New A11 passes over
00:15:46 Nozzano comes into view, with the Apaulian alps in the background
00:15:56 Line from Viareggio runs parallel from Bivio Montuolo to Lucca
00:16:52 We transfer to the "wrong" Viareggio line at PM Montuolo
00:18:07 Montuolo (Closed)
00:18:18 Canale Ozzeri again
00:18:37 Apaulian Alps in the background
00:18:57 A11 passes over
00:22:48 Lucca (Western bay platforms)
00:23:17 The western bay platforms with ETR425.112 leaving with R18570 to Pisa