If we observe here, in 1864 Howrah Delhi was connected as per the author, however disconnected at places and Allahabad bridge was open by 15th August 1865. Delhi bridge on Yamuna river was by 1866. On the last snap by 1889, a company was setup for construction of Ambala-Kalka line for connecting to summer capital of India Simla, indication that line was not yet built. So there is no chance that this train ran on 01 Jan 1866. And 150 years celebrations must definitely be fun.