Puzzle: Railway Track
This is one of those “shunting” puzzles. As you can see in my somewhat clumsy diagram, there is a railway track that goes indefinitely to the right. On the left, it splits into a “Y”, both ends of which merge into a finite straight railway track. There is a coach “A” sitting on one arm of the Y and another coach “B” sitting on the other arm. Both the coaches are 5 yards each.
The distance between the junction point on coach A side and the end of the finite straight track is 5 yards. On the other side, near coach B, the distance between the junction point and the end of the straight finite track is 15 yards. (See pic). In between the junction points on the straight track sits an engine “E” which is itself 10 yards in length.
Like every engine, E can go forwards or backwards and can pull or push the coaches. Any coach and engine can be attached to each other.
Here is the puzzle: Can you interchange the position of coach A and coach B? You have to get engine E back to its original position when you are done.