Sir James Weeks Szlumper JP DL was an English civil engineer. He was Chief Engineer on a number of key railway engineering projects in the Victorian era.

The North Wales Narrow Gauge Railways (NWNGR) was a railway company that planned to build a number of inter-connected 1 ft 11+1⁄2 in narrow-gauge railways across North Wales. The first two of these lines - jointly known as the "Moel Tryfan Undertaking" - were authorised by Act of Parliament 1872 and were built and opened in the 1870s. The original main line ran from Dinas Junction to Bryngwyn and opened in 1877. The second line was a branch from Tryfan Junction to South Snowdon, though shortly after opening, the company designated the Tryfan Junction to Bryngwyn section as the branch, and the Dinas Junction to South Snowdon section as the main line.