How did they find Poirot on that train, in the middle of nowhere??

The ending doesn't make sense. How did (Scotland Yard? British Military Intelligence?) find him on that stranded train, in the middle of winter, in the middle of nowhere? There were no radios on the train; no cell phones; no GPS in 1934. Especially, as Poirot wanted to be incognito and take a vacation.

Also, when that officer at the end fetches him, he says: there's been a murder in the Nile. Which again, pardon the pun, doesn't hold water. #1 - It would take at least 4-5 days for Poirot to get to Egypt. #2 - By which time, the murder would already have been committed, so the scene would ahve been contaminated already. So why would they need him?
#3 - In the original story, he was also on vacation; and the crime happened while he was already on board -- thereby having a fresh take on the investigation.
#4 - If the original story holds, the barge was already out in the Nile, so how would they get Poirot to the barge??

Can anyone make sense of the ending?? (I know it's to set up the sequel of DEATH ON THE NILE.)