No such thing is possible. You can't compare flights with trains. Flights/airports have a lot more security. With trains, you have to forget terms such as limited occupancy and point-to-point services when talking about stranded migrant workers. If such trains are allowed to run, there will be stampedes all along the routes. People stranded en route (and about 100 km around the routes) will flock to tracks and stop these trains to go to their native places. Mind you, these trains will already be super crowded at their super crowded originating stations. This is all too dangerous. Much more dangerous than hunger and COVID-19.
Starting trains for passengers should be the last phase of re-opening the economy.