Infrastructure spending can leak through lost industrial capability

Does infrastructure spending help keep money within the country where it is spent?

Yes, although importing trains based on designs previously sold abroad sends part of that spending overseas.

Domestic infrastructure spending can support national industry, but the benefit depends on where the equipment is manufactured. British rail procurement supplies the example: designs developed to suit an early railway network are sold abroad, then trains based on those designs are bought back when Britain needs them. The criticism concerns losing the ability to supply a domestic requirement after doing the original development work. Infrastructure expenditure can consequently generate manufacturing income overseas even when the railway itself remains in Britain.