Mr. Brinkman was on foot when he was struck, according to Caltrain spokeswoman Christine Dunn.
None of the 518 people on board southbound Caltrain 192 was injured, she said.
The train was moved to the Menlo Park station so the passengers could board another train, she said. Trains do not stop in Atherton on weekdays.
This is the fifth fatality on the Caltrain right-of-way this year, Ms. Dunn said. Last year there were 13 fatalities.