First of all you need to understand that precis is not just shortening of the passage You have to shorten it in a meaningful way.

European trains had to exchange their engines and staff because of National chauvinism This is wrong. They don't change their engines because of patriotism. They change it because of technical reasons or difference in rail systems.

Brussal tried to run better rail network and control on pollution Brussels did not try to run better railway. They just 'strive' to have an efficient and integrated system.

France,Germany and Italy are working hard to develop their own expensive ad mutually high speed- train. This point is connected to the one about Brussels, meaning despite brussels trying to run a compatible railway network, these three countries are working in the opposite direction. Also 'mutually high speed' doesn't make sense to me. The passage only says mutually incompatible which simply means not able to work together(rail systems)

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