I've seen the new Orient Express (21344) set:
It does not include a battery box or motor, and it also doesn't include standard City tracks:
It instead includes custom brick-built rails for display purposes:
Will this train even run on standard track? Can it be motorized to run on standard track?
This train will run on standard track without modification. The gauge of the brick-built track is no different from the standard City track.
There are a number of ways that this set could be motorized. Generally, we need to find a way to power the wheels and stow a battery box to power them.
One approach that has been shared on Rebrickable is to add a Technic motor to the locomotive and place the battery box in the tender:
A disadvantage of this approach is that it requires a complicated rebuild of the locomotive and many additional parts.
An alternative approach as shown by Tom Alphin is to place both the battery box and the motor in the tender:
This is a simple and clean approach (the same as I used on the recent Hogwarts Express), but the motor looks a bit small under the tender, and the tender now has 2 wheelsets instead of 3. Here's the assembled look with the train motor driving the tender:
Here's an example SNCF 230 locomotive such as the one this set attempts to replicate:
Here's the unmodified stock build from the set: (image flipped horizontally for easier comparison to images above)
A related approach that I chose to use was to place the battery box in the tender and place the City train motor under the first coach. This isn't as nice as powering the actual locomotive, but it is much simpler and gets the job done using very few additional parts aside for the battery box and train motor:
The tender is actually already designed to hold the battery box, but a few minor modifications are necessary to allow the wire to exit the back of the tender rather than the front:
Using the modified tender, all that is left is to add the appropriate couplings to the train motor and decorate it as desired. It then replaces the first truck of the first coach and drives the train.
Here's the completed train running nicely:
