In the next exterior shot after departure from Istanbul, a differently colored diesel locomotive is on the train. During the night scenes before the journey is interrupted, a steam locomotive is shown. Then when the train stops at the rockfall, the same EWS diesel is back on it, but now it's facing the other way (the EWS letters and the locomotive number 47744 have swapped places as seen from the same side of the train). Finally, when the journey resumes the next night, the steam locomotive is back.
On departure from Istanbul the first car of the train is named Perseus. When stopped at the rockfall, the first car is Lucille.
Poirot counts 9 stab wounds in the victim (Unlike 12 in the book) yet when the case is shown in flashback we see ten blows with the knife.
While Poirot is examining Ratchett's body for the second time, Ratchett is still breathing.
The diesel locomotive hauling the Orient Express out of Istanbul has the prominent markings of EWS: the English, Welsh & Scottish freight train operating company.