Railways have benefited from such technological improvements as double-stacked rail cars and better software for managing both rolling stock and supply chains.
铁路（公司）也因技术改进而受益，例如双垛轨道车，而且有更好的软件管理全部机车和供应链。
2
In this design, two rainbows are stacked on top of each other in a pixilated form to create an illusion of a double rainbow.
在这个设计中，二道彩虹曲线的顶瑞以一种奇特的方式创造出一道双重彩虹的错觉。
3
The house is in a secluded neighborhood set back about60 yards off a gravel road, surrounded by stacked stone wall and a double-iron gate.