Geography of Kent and Dungeness have been formed by accumulation of alluvium. Kent's principal river, the River Medway, rises near Edenbridge and flows some 25 miles (40 km) eastwards to a point near Maidstone, when it turns north. Here it breaks through the North Downs at Rochester before joining the River Thames as its final tributary near Sheerness. The river is tidal as far as Allington lock, but in earlier times cargo-carrying vessels reached as far upstream as Tonbridge. The Medway has captured the head waters of other rivers such as the River Darent. There are other rivers in Kent, most notably the
Headcorn and Maidstone Junction Light Railway worked by class 08 and 09 shunters, the bridge being deemed unsafe for anything heavier. The line was long and it closed to traffic on 3 October 1977. After closure the bridge over the river was removed and the site of the goods station is now covered by housing. Headcorn and Maidstone Junction Light Railway The Headcorn & Maidstone Junction Light Railway was a proposed railway in Kent. An Act of Parliament authorised its construction, but only a short branch at Tovil, opened to goods only, was built. Maidstone, the county town of Kent, had been reached by the railway