Until the 19th century Folkestone remained a small fishing community with little respite from storms, making boat landings difficult. The harbour was built in 1820, providing a safe haven for boats and trade and the population increased as a result. In the 1840's the South Eastern Railway Company bought the harbour and constructed a rail line down to the pier. The principle use was servicing cross channel steamers plying between Folkestone and Boulogne. In the panorama shot below (stitch of four images), you can clearly see the railway viaduct. Tide was out, but I reckon that adds character to the shot.
[ISO 100, 1/100s, f8; panorama stitched from 4-images using Photomerge in Photoshop CS2]
The major growth of Folkestone occurred between 1848 and 1868 as did its reputation as a seaside resort. Although it is recorded that sea bathing machines were present in Folkestone as early as 1788, it was not until the mid 1800's, with the building of new town facilities and accommodation made possible by the coming of the railway, that sea bathing became a major part of the town's culture and economy. Here's a few more views of the harbour which is probably the most photogenic area I was able to see during my short visit: