Arriving at Butterworth by train you’ll end your journey at Penang Sentral. Penang Sentral is a hub from which you can catch the train, bus or ferry.
If you have been heading north on the train you can continue going north. If going south, you can continue south. Butterworth is on a branch line off the main line. It is also possible if you do not want to visit Penang to go directly to or from the Thai border from or to Kuala Lumpur.
From Penang Sentral there is a train service north to Padang Besar on the Thai border. You can cross the border to Thailand at the station. From there you can transfer to trains travelling north through Thailand. Or you can cross the border at the road crossing and catch buses to other parts of Thailand.
As for the train service south: it stops at cities such as Taiping and Ipoh on the way to Kuala Lumpur, and on towards Singapore.
Alternatively, arriving at Butterworth by bus, you can catch other buses to various parts of Malaysia from Penang Sentral. Finally, there is a ferry service four times an hour, across to Penang Island, a 15 minute journey.
If you are in no hurry, there are plenty of food outlets in Penang Sentral. And coffee shops etc.
So here are some photos and video of what it’s like to arrive in Penang Sentral. And thus moving on the catch the ferry to George Town.