Complex sentence: In 1888, he joined the Caledonian Railway's Drawing Office in Glasgow, where he designed a number of railway stations under the supervision of the engineer-in-chief, George Graham, and his successor Donald Alexander Matheson.
Split into simpler sentences: In 1888, he joined the Caledonian Railway's Drawing Office in Glasgow. There, where he designed a number of railway stations under the supervision of the engineer-in-chief, George Graham, and his successor Donald Alexander Matheson.