I would say there is between me and other people a gap of 1-4 years. But we have news, the internet, video and audio.
So what might be 1-4 yeard today, it might have just been 10-50 years at 1915.
A new technology for the avg person
The locomotive being exhibited in 1915 was a historic exhibition, exhibiting their first locomotive, which itself was actually from 1863.
It was a history piece. It was not demonstrating new technology!
It would be like saying that the first shuttle orbiter, Enterprise, was first exhibited in New York in 2012, inspiring crowds.
It's a pedantically true statement ( it was moved to NY in 2012 ), but it doesn't actually tell you about the state of technology in 2012.