War is the Locomotive of HistoryWatch
If so then yeah, just made improvements happen because war revealed what needed changing.
Doesnt really mean anything else, because the guy who said it was thinking of it as a catalyst.
War is a catalyst for change
A catalyst is something that causes an acceleration in the reaction of something.
Revolution may occur because people want change
There was growing resentment for the Aristocracy in Russia, especially the Romanov Family.
There is an argument that although the Russian revolution was inevitable, the heavy losses in World War I was the catalyst for revolution kicking off in 1917. As a result, the change was that there was no more Romanov family to rule. No more aristocracy and Russia made a transition from Autocracy to Communism.
The political, social and economical structure was the change.
The war was the catalyst.
I think a really interesting aspect of it is the context. Trotsky said it after he won the Civil War - this war has pushed along history in its rightful path, almost. But also, as a locomotive is part of a train, it symbolises how Trotsky, using an actual locomotive, was acting as the locomotive of history - the armoured train he used to fight the Civil War was a symbol of the Reds who would modernise the country (not to mention the propaganda station it had on board).
Looking at evidence of revolutions we pretty much concluded war isn't the only force that makes history move (as Trotsky would have said in 1922) - ie the Iranian revolution had very little, if anything, to do with military matters. However, when there's a war, especially with a losing country, often big changes happen, making history.