Border-crossing lines are utterly fascinating. The traditional visual signalling system tends to change exactly at the border, but you may find pre-signals just

Border-crossing lines are utterly fascinating. The traditional visual signalling system tends to change exactly at the border, but you may find pre-signals just inside the other country. The in-cabin signalling and automatic train protection may or may not change at the same location. Changeover of the electrical system is more elaborate, and can take place at the border, a few kilometers inside one of the countries, or at one of the larger stations on either side, in which case you will find switchable tracks at that station. There are different allowed widths and heights ("loading gauge") for train cars in different countries. Finally, few people know that the overhead lines veer a little bit to the left and right to spread the wear on the pantographs. The extent to which this happens also differs between countries, and some countries have narrower pantographs than others, which means that trains cannot just ride both in Germany and Switzerland even though they have the same electrical system.