It's rather a positional call if that's a good idea or not...
Yeah, I'm inclined to say it's not a good call.
Where do you build afterwards? You now need an additional line elsewhere to complete a link, so was it worth 2 resources later to get one gold now and deliver one cube ASAP? If you instead fork a different path off that line, you're doing so on a line that has an opponent's train already on it, and that can be troublesome.