No it's generally not...
Trains are heavy and require a lot of energy to move them, and in most cases don't take you directly where you need to go so you might have to take an indirect (ie longer) route, and will usually have to travel to/from the station at either end.
In order to get close to the claimed energy efficiency benefits over cars, trains are often packed well over their design capacity - that means no comfortable seats, you will be standing with other passengers right in your face.
Those trains which are sufficiently quiet that you actually get to sit in a comfortable seat are nowhere near the claimed level of energy efficiency.
Trying to force more and more people into overcrowded trains and buses might increase energy efficiency, but it is very unpleasant for those doing it. A much better solution is to simply reduce people's need to travel, which covid proved does work.
This means remote working when the job allows for it, and for jobs that are unsuitable for remote work designing cities so that employees can live closer (ie within walking distance) of their workplaces.
If you eliminate most of this unnecessary daily commuting you'll easily exceed the 3% target.