Few things which I noticed over the years at Pune Station (in brief):
1) WDG2 getting replaced by WDG3A, later by Shakti Engines
2) WDM3A getting replaced by WDM3D
3) Beginning of WDG4 and WDP4 (of SWR UBL / KJM Shed) entering Pune
4)...
more...

Lots of New Trains Introduced to/from/through Pune, Frequency of many trains increased
5) Expansion of PUNE DLS to hold new WDM3D, then WDG4 then WDP4D and now WDG4D
6) DC Traction changed to AC from Pune to Lonavala (Ghats still under DC then) - leading to end of good old WCG2 Locos coming to Pune
7) Passenger Load / Travelers increased by Leaps & Bounds over the years
8) Cleanliness of Pune Station getting bad to worse to worst and now to worstest!
9) BL WCAM1 Locos at Pune handling WR bound Trains (later phasing out of these good locos)
10) KJT-LNL Section then coming under AC Traction allowing entry of WAG5/WAG7 and later WAG9 locos to Pune
11) KYN coming under AC Traction allowing entry of WAPx locos to Pune
12) In the mean time, good old WDS4/4B/4D as well as WDS6 shunting locos vanished from Pune
13) Lots of WDM2/3A scrapped and others converted to WDM2S (fit for shunting work)
14) Many Loco Link Changes to/from/through Pune, KYN getting WCAM2/2P locos
15) DUW (Diesel Under Wires) Increased over the years (contrary to belief that it should reduce day-by-day)
16) Mumbai CSTM coming under AC Traction thereby allowing any type of E loco to be allotted to any train