过道/走廊 what's the difference?
For buildings, according to 住宅设计规范(Design code for residential buildings) GB50096-2011,

2．0．13 过道 passage
　　住宅套内使用的水平通道。
2．0．20 走廊 gallery
　　住宅套外使用的水平通道。

So the internal transport space, such as the passageway inside the cinema or train, can be said as &quot;过道&quot;.
And the transport space which is outside the building, independent, covered, can be said as &quot;走廊&quot;.
Except for buildings, &quot;走廊&quot; can also be used for a narrow strip(corridor) connects two areas. Such as &quot;河西走廊&quot;.