About 28 percent out of nearly 1,000 trained employees left the project last year, making it difficult for the city to proceed with it, Hanoi Chairman Nguyen Duc Chung said Friday.

The city has recruited and trained thousands of people to prepare for the project’s commercial operations. Around 200 were trained in China.

Chung said there were four major unresolved issues regarding the metro line’s contractor, the China Railway 6 Company.

The first involves the state assessment council, which evaluates and inspects the safety of the whole system. Their job has been delayed because they need the documents that verify the origin of the equipment used for the project to see whether they meet required standards. The contractor has not submitted these documents.

Second, the project must be audited, but this has not been done. Chung said the project must comply with Vietnamese laws, and that the Vietnamese auditing agency has the right to do its job. He said the contractor must be accountable and follow the procedure.

The contractor must also follow up on the recommendations made by the auditors, ranging from matters related to design, site clearance and the construction, he added.

Furthermore, the contractor should coordinate with the Ministry of Transport to complete the supply of equipment as agreed in the contract.

Regarding the railway's progress, Chung said "if all goes well" the project should begin commercial operations by the end of December.

The Cat Linh-Ha Dong route, Hanoi's first metro line, runs 13 kilometers from Cat Linh Station in downtown Dong Da District to the Yen Nghia Station in the southwestern Ha Dong District.

Operators began a 20-day commercial run for inspection purposes on October 29.

The project has experienced several delays, the latest due to the fact that the Chinese contractor has not provided certificates and documents to be perused by foreign experts for evaluating the system’s security, the Ministry of Transport said in a report earlier this month.

Meanwhile, Duong Hong, Director of the Cat Linh - Ha Dong Railway Project, has said that the company has provided all the documents to the Vietnamese investor. The investor has made other additional demands that are difficult for the Chinese contractor to meet, he said.

Work on the Cat Linh-Ha Dong elevated railway started in 2011 and was originally scheduled for completion in 2013, but several hurdles, including loan disbursement issues with China that were only resolved in December 2017, stalled it for years.

The original project estimate of $552.86 million has also ballooned to more than $868 million, including $670 million in loans from China.

Hanoi plans to build eight urban railway lines with a combined distance of 305 km, including three monorail segments, as per its development plan for 2030 with vision towards 2050.