The director says he took inspiration from a news story about the Ford V8 engine's restoration by Allahabhad-based mechanic Hashmat Ullah. He has roped in veteran actors Paresh Rawal, Om Puri and Pavan Malhotra apart from Gandhi's grandson Tushar, who plays himself in the film.
"I got the idea for the film from a news story that came on NDTV two-and-a-half years ago. It showed that the vehicle that carried Gandhi's ashes in 1948 had been reduced to junk and was restored by a Muslim guy, " Rai told over telephone from Mumbai.
"It made me curious and I started working on a story around it. While I was researching, I found out that of the 22 urns carrying Gandhi's ashes that were sent across India to be immersed in different rivers, one was found kept in the Orissa State Bank of India locker.
"I tried to arrange the facts in chronological order so that it becomes a story. I tried to weave a story that talks about the principles of Gandhi in the midst of the whole restoration process and the procession to Sangam, " he added.
The vintage vehicle was lying in a state of disrepair at a museum in Allahabad until Hashmat Ullah restored it. The remains of Gandhi's ashes, which had been kept in the locker in Orissa, were carried on the same vehicle and immersed in the sea in Mumbai on his death anniversary Jan 30, 2008.
In the film, the main protagonist played by Paresh Rawal is called Hashmat Ullah. The director says he wrote the story before meeting the mechanic in person.
"I met Hashmat Ullah in person only after I finished writing the story to take his confirmation to use his name for the mechanic's character. Initially I had planned Mohammed Hafiz as the character's name, but then I felt I should replace it with Hashmat's name as he is the one who did it, " Rai said.
Set in Allahabad, "Road To Sangam" revolves around Hashmat caught in a complex situation when a bomb explosion rocks his town leading to the arrest of innocent Muslims from his locality. A strike is called by prominent Muslim leaders to protest the injustice meted out to the arrested men. Hashmat is then in a dilemma about whether to support his community or go ahead and repair the engine.
"The film is a journey of Gandhian values and principles and a journey of patriotism. The treatment of the film is very commercial, but the message is very non-commercial. Besides Hashmat's name and the fact that he restored the engine, rest all is fiction but not woven like fiction. It will be seen as a real story by audiences, " said Rai.
Produced by Gipsy Films, it has been made at a budget of approximately Rs.6 crore (Rs.60 million) and Rai has decided to release the film on Mahatma Gandhi's birthday Oct 2.
Asked if it was difficult for a debutant director to rope in seasoned actors like Paresh Rawal and Om Puri, he said: "It was the story that attracted them and all actors were ready because of my script. Paresh Rawal gave his nod immediately and Om Puri suggested some changes on the sets... he advised not to imitate the real mechanic at all and create our own character."
Having already generated a buzz in the festival circuit, "Road To Sangam" had its world premiere at the Ahmedabad International Film Festival this year. It was also screened at the 62nd annual Cannes Film Festival to a "standing ovation and a second screening on-demand".
Active in theatre for the last 12 years, Rai has been a three-time recipient of the Best Director award at the Maharashtra State Drama Competition.
He has also been an assistant to directors like Anurag Basu and Anurag Kashyap and was associate director for critically-acclaimed Marathi film "Tingya" (2008).