Tum solid development and trustworthy development mein confuse ho gaye ho.
Mere hisaab se solid development ka matlab yeh hai ki Jo development/improvement hua hai , wo bana rahe. Aisa na ki, kal Gatimaan chala diya and agle hafte usko scrap karke kuch aur chalwa dia. I mean kal se agar Gatimaan chal rahi hai toh usey abhi atleast continuous chalte rehna chahiye , till the time RDSO and RB permits 180-200 kmph trains.