The Tesla Semi has completed a 500-mile trip with a load weighing 81,000 pounds, Tesla owner Elon Musk tweeted Saturday.

The first test run was an important step for the Austin, Texas-based company’s all-electric Class 8 commercial truck, which was supposed to be in production in 2019.

Tesla’s Semi program has suffered repeated delays, including the departure of a key executive and supply chain issues. Tesla (NASDAQ: TSLA) first announced the Semi-truck back in 2017.

The Semi truck’s first deliveries are scheduled to PepsiCo subsidiary Frito-Lay sometime over the next several weeks. Tesla has already installed a Megacharger on a Frito-Lay distribution site in Modesto, California.

Along with PepsiCo, the Semi has attracted thousands of orders from fleets. Mass production of the Semi — up to 50,000 units per year — is expected to take place at Tesla’s Austin Gigafactory, which also produces the Model Y electric vehicle.