If you play through all the levels from 1 to 50 once, you should have most of the achievements. You may have to play a random level here or there if you have 99 railways out of 100, but the one achievement you will definitely be very short on is "Outstanding Engineer." You need to build 100 bridges, but a single play-through of all 50 levels will only net you around 70 bridges.

A glance at the list of Steam Achievements for this game will show that only 16.5% of most people who have played this game have gotten this achievement, even if they have gotten all the others.

Here is a simple solution: Play level 25 two or three times. Level 25 has eleven bridges, and you can easily gain the "Outstanding Engineer" achievement in about a half hour or less.