Trains r expensive and time consuming. More than 52 departures everyday (avg 2 flights every hour) between mumbai and delhi and all are mostly full. Airlines will takeover railway lobby soon under UDAN scheme. In trains we see WL only because of intermediate stations. I recently booked 2AC in golden Temple mail from NZM to BVI 5hrs before departure and got WL51 and it got confirmed. What I observed was that train was vacant from NZM to KOTA and then from RTM to BVI only short distance passengers and it took me almost 19-20hrs