轨道电路区段道床顶面低于轨枕顶面。哪个选项是正确的? A.20mmB.25mmC.30mmD.40mm
轨道电路区段道床顶面低于轨枕顶面。哪个选项是正确的?
A.20mm
B.25mm
C.30mm
D.40mm
相关考题:
9、道床顶面宽度与轨枕长度和道床肩宽无关。
A.20mm
B.25mm
C.30mm
D.40mm