The Delhi- Meerut Regional Rapid Transit System, also known as Delhi Meerut RRTS, Delhi Ghaziabad RRTS Meerut RRTS and coloquially Rapid Rail, is an under-construction and partially operational 82.15 km (51.05 mi)-long semi high-speed rail and regional transit corridor that will connect the National Capital Region (NCR) cities of Delhi, Ghaziabad and Meerut.