I think it's a valid connection to see the train death as connected to Tolstoy. Pasternak was certainly not a proponent of the Tolstoy sort of idealism, though. His peasants are perhaps good people (Anfim Efimovich, for example), but they are certainly not people who should be leading a country. The form of government the peasants would have chose would resemble Meluzeevo - backwards, superstitious, mixing Christianity with ideas about magic and ultimately anti-intellectual (and, for that matter, irrational).

It would be another example of Pasternak turning other authors on their heads. The other one I can think of is his refutation of Mayakovsky in the figure of Komarovsky. Mayakovsky had a bulldog named Jack and took walks exactly where Komarovsky did, and in Pasternak's letters he cites things that Mayakovsky said to him which sound almost word for word like what Komarovsky says to Zhivago. The parallel, then, shows that Mayakovsky was a self-interested prostitute who used the Bolsheviks for his own ends (and then, ultimately, could not control them).