Between March 3 and March 5, 2026, the Kanto Transport Bureau conducted a safety audit of Kominato Railway Co., Ltd. Based on the audit results, the company was found to have unresolved issues related to track maintenance, notably significant elevation differences and inadequate drainage functions. Although the company had previously reported plans to address these issues by February 2026, progress was not as planned, and no measures had been taken to complete repairs or to develop necessary plans for drainage and ballast replenishment. The bureau instructed the company to formulate an appropriate repair plan that includes drainage improvements and ballast replenishment, and to coordinate with relevant local authorities as needed to ensure proper maintenance. The company was required to report on the measures implemented by July 28, 2026.

Between March 3 and March 5, 2025, a safety audit was conducted on Kominato Railway Co., Ltd. by the Chiba Prefectural Public Transportation Authority. The audit identified several areas requiring improvement, including inspection records, safety management systems, construction procedures for railway facilities, personnel training, and operational procedures. The authority has instructed the company to implement corrective measures and report on these actions by August 14, 2025. The guidance emphasizes establishing a system for regular verification of on-site operations, ensuring inspections are conducted and recorded properly, and reviewing safety regulations related to track maintenance, construction, personnel fitness, and operational procedures to ensure compliance with the Railway Business Act and related ministerial ordinances.

On January 15, 2024, Minato Railway Co., Ltd. (corporate number 8040001053928), based in Ichihara City, Chiba Prefecture, reported to the authorities that one of its drivers (hereafter 'the driver') had operated a train or vehicle without conducting alcohol tests using an alcohol detector before duty, and that another person had substituted for the test, falsely passing it. An audit was conducted on January 17, 2024, which identified issues requiring improvement. The company was instructed to verify the appropriateness of operational methods, implementation status, and management related to these issues, investigate the root causes including underlying factors, and develop measures to prevent recurrence, ensuring the safety of railway transportation. The company was also asked to report on the corrective actions by March 8, 2024. Specifically, it was confirmed that the driver had repeatedly allowed a conductor to substitute for alcohol testing using an alcohol detector while the station staff was away, and on October 19, 2023, the driver turned off the alcohol detector during testing to avoid detection of alcohol, refusing re-test instructions and instead having the safety officer conduct the test. The guidance emphasizes the need for thorough safety awareness regarding alcohol consumption, compliance with laws and regulations, and the establishment of a system for accurate on-site situation awareness, with regular verification and improvement. Furthermore, the guidance references the interpretation standards for technical regulations related to railways, specifically regarding the education and training of personnel directly involved in train operations ('operation personnel'). It was confirmed that the company’s implementation guidelines do not specify necessary details for training and record-keeping, and that records of training are not maintained, making management and verification difficult. The company is instructed to include these details in their implementation guidelines, maintain records, and properly manage the training process. Failure to comply with these instructions, or if safety management improvements are not confirmed, or if violations recur, may result in orders for business improvement based on relevant legal provisions, including the Railway Business Act Article 23 and the Administrative Procedure Act Article 35, which authorize such measures when safety or public interests are deemed to be hindered. This guidance was issued by the Kanto Transport Bureau.

Between October 19 and 21, 2022, a safety audit was conducted on Minato Railway Co., Ltd., based in Ichihara City, Chiba Prefecture. The audit revealed several issues requiring improvement, leading to instructions for corrective actions to be taken by March 31, 2023. The identified deficiencies include: 1. Lack of an annual training plan for staff involved in train and vehicle operation, contrary to the report from October 12, 2016, which stated such plans were to be created at the beginning of each fiscal year and approved by the Safety Promotion Committee. 2. Inadequate facility maintenance, including exceeding inspection cycles for track patrols and failure to record inspection results for rails, ballast, and track markers, violating the standards set in the Track Construction Standards. 3. Failure to conduct periodic inspections of electrical safety equipment, specifically the insulation testing of high-voltage distribution cables within the prescribed period. 4. Vehicles, including rolling stock, were inspected outside the scheduled cycles, and management of inspection data and schedules was insufficient. 5. Records of important inspections for trolley vehicles, including outsourced tasks, were not properly maintained, with missing records for specific inspections such as the clearance measurements between the axle box and the axle. 6. Several train drivers did not submit required qualification management reports after mental health assessments conducted between April 8 and May 18, 2021. 7. Inadequate health and pre-duty checks for train drivers, including incomplete vision tests and failure to verify corrective eyewear conditions before duty. 8. Organizational changes made on February 1, 2019, to unify crew call procedures were not properly reported to the authorities, violating the Railway Business Act and its enforcement regulations. The company was instructed to investigate the root causes of these issues, implement corrective measures, and report back by the specified deadline, ensuring compliance with the Railway Business Act and related technical standards.