Stretching over 70,000 miles, India boasts one of the largest rail networks in the world. But it's also the deadliest. Thousands of people die every year in train accidents in India. Now Prime Minister Narendra Modi's government is making rail safety a priority. It has promised to invest $100 billion over the next five years to help the creaking network get back on its feet - and improve its terrible safety record. Our correspondents report.
