You’re not accounting for the substantial differences between the physical contexts in which trains and aircraft operate; the physics in play are wildly different, and have substantially different risk profiles due to that.

If an engine breaks…

• on a train: the train stops.
• on a plane: depending on the situation, the plane has to make an emergency landing in the next case, and everyone dies in the worst case

If a structural issue exists and begins to spread:

• on a train: it can be catastrophic, but the situation will likely devolve in a more segmented fashion, simply because trains move far slower than planes do.
• on a plane: it will almost certainly be catastrophic, and the situation commonly devolves rapidly, if not nearly instantaneously, because passengers jets normally operate around .85 Mach.

More generally: the difference is that the “catastrophic spectrum” that can affect aircraft is much broader and has far more extreme consequences - as in, passenger survivability is often all or nothing, or at least very close to it.

Edit: not to mention: you’re talking about Indian trains, which are in notoriously poor repair, and commonly operate at passenger capacities that would give most European, American, Korean, Japanese, or Chinese civil engineers a serious case of hives. Also not to mention: if this is the accident to which you’re referring, the fatality rate was ~25% - obviously not great, but if a similarity catastrophic air incident were to have occurred (e.g. a midair collision), the fatality rate would have been 100%.