The Newtown and Machynlleth Railway was a railway company in Wales. It built a line from a junction with the Llanidloes and Newtown Railway near Caersws to the market town of Machynlleth; the line opened in 1862. Newtown had become the hub of railway lines in the district. Machynlleth was an important town, and extension from there to Aberystwyth and to the coast northward was in the minds of the promoters.