These tiers could categorize methods of operation in conjunction with safety improvements such as separation of passenger and freight traffic and advanced train control systems.
这些安全措施包括将客运流量与货运流量隔离，升级列车控制系统等。
2
As an advanced model of transportation organization, the system of highway express freight transportation has realized rapid, safety, right and "door-to-door" service.
公路快速货运系统作为一种先进的运输组织形式，能够提供快速、安全、准确和“门到门”的运输服务。
3
This paper introduces the advanced electronic commerce system of automatic match form of highway freight transport.