单项选择题
A.3B.4C.5D.2
A.双块式轨枕B.道床伤损C.底座板伤损D.支撑层伤损
A.CRTSⅠ型板式无砟道床B.CRTSⅡ型板式无砟道床C.道岔区轨枕埋入式无砟道床D.CRTSⅡ双块式无砟道床