The train, carrying 20 wagons of 40-m containers, started its journey on June 27.
"This is the first inbound trip; we hope that there will be more trips between the countries," said Keretapi Tanah Melayu Bh (KTMB) chief operating officer Mohd Zain Mat Taha as quoted by the Malaysian newspaper The Star.
He noted that the one-way trip took about nine days and crossed Thailand, Laos, and China.
The schedule for the next cargo train and its frequency is unconfirmed. However, KTMB corporate planning head Abdul Salim Shah Abdul Aziz said that they currently expect two to three trips a month.
As the service grows, there will be daily trains, he added.
The ASEAN Express is expected to boost trade connectivity between Malaysia, Thailand, Laos, and China as it is a faster mode of transportation, taking nine days for goods to reach China as compared to between 14 and 21 days by sea.