I am surprised to know that dynamic pricing was introduced back in 2006-07 Rail budget however the that was different from the dynamic pricing applicable today..
Here is the full text.
Dynamic Pricing Policy
111. Railways' passenger fares and freight rates remain unvarying for all seasons and for all routes, whereas tariffs in the airline and road sectors vary depending upon...
more... the demand and the season. In order to be able to effectively face the challenges posed by stiff competition, in the current year we had started a discount scheme for non-peak season and empty flow direction for freight rate, which has been successful. As an extension of this policy, I propose to introduce a Dynamic Pricing Policy for freight as well as passenger, for peak and non-peak seasons, premium and non-premium services, and for busy and non-busy routes. As per this policy the rates for non-peak season, non-premium service and empty flow directions will be less than the general rates and the rates for peak season and premium services could be higher than normal. For the freight the non-peak season would be 1st July to 31st October. For the passenger segment this period would be 15th January to 15th April and 15th July to 15th September.