脱轨的英文：
leave the rails
derail
jump the track
run out of track

参考例句：

The streetcar was derailed
电车脱轨了。

split - switch derail
尖轨式脱轨器

A device for shifting gears on a bicycle by moving the chain between sprocket wheels of different sizes.
脱轨器，转撤器通过在不同大小的扣链齿轮间移动链条而转换自行车齿轮(换档)的装置

leave是什么意思：
v. 离开；出发；舍弃；脱离；辞去；遗忘；听任；留下；交托
n. 休假；许可；辞别

To leave;vacate.
离开；撤出

I leave that to you.
这都留给你啦。

Leaves die, fall, and shrivel.
叶子凋零、飘落枯萎了。

rails是什么意思：
n. 铁轨；横杆，扶手；抱怨，痛斥

To supply or enclose with rails or a rail.
用栏杆围提供栏杆或把栏杆围起来

The coal will be shipped by rail.
这些煤将用火车装运。

Trains run on rails.
火车在轨道上行驶。

derail是什么意思：
v. （使）脱轨

The inexorable rise of china has not been derailed.
中国不可阻挡的崛起并未脱离轨道。

The passengers were bumped out of their seats by the derailment.
火车出轨道使乘客们都被颠离座位。

The engine was derailed by a tree lying across the line.
有一棵树横在铁轨上,造成机车出轨.