A.50mm B.100mm C.150mm D.200mm
A.既与铁路等级有关又与地形有关 B.只与铁路等级有关 C.只与地形有关 D.既与铁路等级无关又与地形无关
A.400m B.800m C.600m D.4000m
A.C61、C63、C63A B.C62A、C62B、C64 C.C61、C62A、C62B D.C63、C63A、C64
