The 12431 / 12432 Hazrat Nizamuddin - Thiruvananthapuram Rajdhani Express is a Rajdhani Express train service in India, connecting Hazrat Nizamuddin in the country capital New Delhi to Thiruvananthapuram Central, the capital of Kerala state.It is the longest-running Rajdhani Express train in India, which covers about 2845 km in about 42 hours.