Dear friend, as far as I remember, Mumbai Pune Shatabdi was introduced in 1996 by the then MoS (independent charge) for Rlys, Mr. Suresh Kalmadi during his short stint in Rly ministry. Shabby coaches of DQ were also replaced by brand new rake.
The Shatabdi had a small rake of about 6/7 CC, 1 EC & P coaches. TT was 2027 CSTM dep16:25/ Pune arr 19:45, 2028 Pune dep7:45 /CSTM arr 11:05. i.e. just 5 minutes lesser than Deccan Queen (3hr 25min). Since unlike DQ, 2027 did not have halts at lonavala & Dadar, it can be said that its actual running speed and priority was no more than DQ. Later it slowed down by 5 minutes with stops...
more... at Dadar, Lonavala (just like DQ).
It failed mainly due high fares and availability of good alternatives by way of buses & taxis between Mumbai & Pune. At that time train fares (especially ac fares) were much higher as compare to purchasing power (avg income) of people, and ac travel was not very common with trains at an average used to have 2 ac coaches.
Completion of Mumbai-Pune expressway in 2002 tilted the equation in favour road which facilitated shorter and faster travel.
In Jul'03 tt Shatabdi was speeded up by 30 minutes (6:50-9:45,18:00-20:55), but still the traffic was elusive. After a prolonged duration of poor patronage and a strong public demand, it was converted into intercity express numbered 2127/2128 and non ac coaches were attached keeping the train timing same.