How to calculate a route / find waypoints between start and destination

[Aussiebear]

Let me show you, perhaps you can suggest me an approach to the final solution.

However, how would you know the correct waypoints if there were another line involved? For example, something like this:

A	B	C	D	E	F	G	H	J	Z
3	3	3
			1	1
	4				4	4
			6		6			6
2		2		2
							5	5	5

The correct answer in this case should be: start A in 3 -> then go to 4 in F which turns to 6 and finally J goes to Z in line 5, so waypoints B, F, and J. Waypoint C or A would be mistakes because no further waypoints in 2 reaches destination.

How could anybody deduce that? A simple matrix has predefined values for both Rows and Columns. You provided Column Values only. Does the cell values represent Train numbers or Line Numbers?
In the attached workbook there are two examples of a table layouts (Lines/Waypoint, resulting in Train values and Trains/Waypoints resulting in Line values).

Perhaps looping and taking out those waypoints that don't reach destination (broken route)??

How about you construct a table layout showing which Waypoints lie in which Lines, and show us that bit before this breaks down completely.