Solve Hard Math Riddle: Commuter & Wife Puzzle

[Physic lover]

Hello everybody
Here is a wicked math riddle. Go ahead and see if you can solve it
A commuter is in the habit of arriving at his suburban station each evening at exactly five o’clock. His wife always meets the train and drives him home. One day he takes an earlier train and arrives at his station at four o’clock. The weather is pleasant so instead of telephoning home, he starts walking along the route always taken by his wife. They meet somewhere along the way.
He gets into the car and they drive home arriving ten minutes earlier than they usually do. Assuming that the wife always drives with a constant speed, and on this particular occasion she left just in time to meet the five o’clock train, can you determine how long the husband walked before he was picked up?
The source is my best mathematical and logic puzzles book

 

[mfb]

Interesting puzzle (but not hard in my opinion)

Hint:

Spoiler

Draw a sketch

Spoiler

The arrival time of the first train does not matter. It is not possible (and not relevant) to determine the time it takes to drive home.

 

[Jonathan Scott]

As far as I can see, if the question was changed to "At what time was the man picked up?" you wouldn't even need to know when the earlier train arrived.