In 1887, Beckett was appointed a district engineer with the Bengal-Nagpur Railway in India. He became an associate member of the Institution of Civil Engineers in 1889 and a member in 1895. He was promoted to superintending engineer in 1900 and chief engineer and acting general manager in 1901. He was particularly noted for his bridging of the rivers in Orissa, for which he was awarded the Stephenson Gold Medal and the Telford Premium. The largest and most challenging bridge completed as part of these works was the construction of the first rail bridge over the Mahanadi River at Cuttack, which was completed in 1900.[2] From 1900 to 1904 he was government representative on both the Calcutta Port Trust and the Calcutta Corporation.
In December 1889 William Beckett married Bessie Drummond Thomason, fourth daughter of Major-General Charles Simeon Thomason and granddaughter of James Thomason, lieutenant-governor of the North-West Provinces from 1843 to 1853 and founder of the College of Civil Engineering at Roorkee. Major-General Clifford Thomason Beckett and Captain W. N. T. Beckett RN were his sons.