UPDATE February 19 - Big Thunder Mountain has reopened on schedule after its annual refurbishment. There doesn't appear to be any obvious changes or upgrades to the ride so we assume the refurbishment addressed necessary maintenance to the ride system.
It is usual during the winter months to see numerous attraction closures for routine maintenance. We have just seen Splash Mountain reopening at Magic Kingdom after almost a month long refurbishment.
Big Thunder Mountain Railroad is now closed for routine maintenance and is due to reopen on Saturday February 19, 2022. It is likely that guests won't even notice any change to this iconic attraction but the essential work would have been completed. Be sure to check the official calendar if you are planning to head to the Magic Kingdom at the weekend as the schedule may change.
We are still waiting for news on when Walt Disney World Railroad at Magic Kingdom will reopen. This highly popular attraction was closed at the beginning of 2019 due to the construction of the upcoming TRON Lightcycle / Run. With work near completion on TRON Lightcycle we are hoping to see a reopening for Walt Disney World Railroad very soon.