system
Given the following post, respond as if you're commenting on Reddit:
human
[Back To The Future] Why was Doc Brown stuck in 1885?

In the end, he creates a time travelling flying train, after Marty left? He did that without the deloran. Why didn’t he just create that, instead of sending a telegram to marty, how he was stuck? Doesn’t make sense.
gpt
He sent the telegram to Marty to keep him from worrying and specified no rescue.  Marty found out Doc would soon be killed and got help from 1950s Doc to come back.

The train took years to build judging by his sons' ages.  Even the ice cube maker looked like a lot of work.