Increase in run time is definitely not the solution for Durontos.
For Example, 22210 which used to arrive BCT at 5pm but the arrival time was changed to 4:15 pm. A full 45 MINS early!.
Then, There is 12273/12274 Howrah Duronto with Hybrid LHB rake but it takes exactly the same time as taken by 12301/12302. similar example is from your state too, SC Duronto and SC Rajdhani. Infact, SC Duronto takes 30 mins lesser time than Rajdhani. so, Yes Howrah Rajdhani taking 3 extra halts i.e parasnath, gaya and Allahabad, matters and...
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in the meanwhile duronto can speedily go forward, keeping in mind that this section Gaya-Cnb is one of the high speed section and hence duronto can surely arrive and it actually arrives not 30 mins. so, delaying the duronto by intermediate divisions, as the train dont offer them service is highly unfair.
Departing at night or morning, express and goods trains are there in both the periods. But Timetable was set up by Railways itself, that this timetable for high speed duronto which hapns to be faster than the rajdhanis is possible and the train ran ontime in early start of the train but now, it reaches max time late. Max increase by 10 mins in travel time was ok but it shouldnt be delayed at such regular intervals. Its not like the train is not in demand. It is in demand and hence was her frequency increased. It mentioned as Rajdhani type train in official site, then why such differences? Rajdhani timings are good then shift the duronto also in this timing but it makes no sense to increase her running time by more than 10mins as already 10mins increase is done.
One more solution can be separate lines for goods train as Western Railways have planned DFC i.e Dedicated Freight Corridor.

How can u compare the reduction in time of NDLS-BCT duronto and increase time of NDLS-SDAH duronto??
16hrs 45mins is too much time for a non stop train in such a hig speed NDLS-BCT section
As SK Raj takes 17 hrs with 12 intermediate halts.
So u cannot compare the two.
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one more thing is in NDLS-HWH section the duronto is faster but in most of the other sections either Rajdhani(BCT Raj/TVC Raj) or even GR(BDTS GR) is faster or both have the much similar schedule(MAS Raj/SC Raj).
With increase in passenger/goods traffic on grand cord, the time taken to cover distance will defintly increase day by day, as duronto doesnot have slack time in the schedule. But the rajdhanis have atleast 10-15mins slack build in the schedule, which they tend make on the long run, which the duronto fails to do.

I am not doing comparisions. I am saying that in general, It makes no sense to keep the duronto travel time much longer, just because there are goods train and Rajdhani's pride should be maintained. Duronto service as well cost is close to same as that of Rajdhani and is mentioned as Rajdhani type train in the official site. Plus one point is there that they dont take extra halts that rajdhani takes and hence, they are faster than the rajdhani counterparts like SDAH drnt, HWH Drnt, YPR Drnt, SC Drnt(down direction), BBS Drnt and it also replicates the rajdhani like Mas Drnt. Only section of slower speed for duronto is WR. I had co-passenger in 12951, a WR signal man. He was not ready to accept the fact Sealdah drnt take lesser time than the Hwh Rajdhani. He was telling that this is never possible. so, I can guess...
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the mentality of WR crew about slow speeds of ERS NZM Drnt and BCT NDLS Drnt.
And for your this statement ......''''''''Both being having same speed restriction, covering almost same distance and enjoying equal priority then how can railways expect it to cover it in almost 30mins faster???''''''.......... The fact is there is no need to expect!! as Reality is Duronto takes 30 mins lesss than the rajdhani .
Again coming to your this statement in relation to comparision of HWH Raj and SDAH Drnt i.e drnt being 30-40 mins faster and rajdhani taking two extra halts.
I gave an example of DOWN 12285 SC Duronto and 12437 SC Rajdhani. Rajdhani takes just one extra halt and still duronto take 30 mins lesser than the rajdhani to arrive NZM. Comparision here is of Hybrid LHB Rake of mps 120kmph and icf Rajdhani rake of mps 130kmph. Tracks same as those of the fastest train of india, which might be surely touching 130kmph atleast. Still the hybrid lhb with max 125kmph mps manages to reach with 30 min lesser time than the icf rajdhani that has mps 130kmph. so, This proves that a extra halt may matter in the case of down SC Rajdhani and Drnt to make a diff of 30 mins. so, definitely HWH Rajdhani taking 2 extra halt will surely increase its travel if hwh raj is to b given sdah drnt travel tym. Plus MGS-NDLS Route is the most busy route of India... 6 Rajdhanis, 4 GRs, 1 yuva, 4 Drnts, 2 shatabdis, so many sf & non sf plus special trains. so, it not easy for a train i.e HWH Raj to take halts and also cover the travel and get equal to duronto, which avoid those halts.
And about Comparisions yes, surely can made. In busy route, MGS-NDLS, Duronto run faster than thier rajdhanis counterparts i.e hwh drnt than sdah raj, sdah drnt than hwh raj, bbs drnt than bbs raj. Then why cant the duronto run with high speed in WR section????? BCT-NDLS route is surely not as packed as packed as MGS-NDLS route. BCT-NDLS, ERS-NZM can surely do great speed but are purposely neglected. ERS Drnt doesnt have that much filling but still that doesnt mean slower the so called non-stop train as it doesnt provide intermediate halts

Rajdhani have slack time then it proves that they r made to wait! thats nt the reality. 5 Rajdhanis run back to back and you say they have slack time? and in UP direction, 5 Rajdhanis are joined by a Shatabdi and ofcourse 12259 Drnt at Kanpur. After Kanpur, these 5 Rajdhanis, Kanpur Shatabi and SDAH drnt run back to back upto NDLS. HWH Rajdhani runs like jet, so, I dont feel it might be having slack time instead it is made slow in GZB section but hardly it might be coming to an halt by the reason of slack time. Most reason of coming to an halt is repair work or traffic. Otherwise, Hwh Rajdhanis on avg arrives 10 mins early. these 10 mins are not enough! Once it departed kanpur 40 mins late and arrived ndls just 15 mins late. It means that it has full capability of arrrving...
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40-15= 25 mins early! i.e around 9:30 but its not allowed so, that timing is also ODD timing ? or it is slack time? stick to one thing.
Infact Duronto timetable is so that it runs so fast that it tries to get closer this group of 5 Rajdhanis in up direction and in down direction, easily it can do wonders as upto MGS its night tym and hence can be made to do high speed runs. Then Mgs-Dhn-Sdah is her own vicinity of ECR and ER, where she should be given same preference as that of rajdhani , then also she is delayed. Putting in goods trains in between and delaying the exp trains but yet the result is both goods n exp trains r delayed. then why to delay the rajdhani type duronto.