Looking for passage to South America in 1880s

[lizb]

I am looking for three of my family who went to South America in the late 1880s (possibly in 1889) to help build the railway there.
I am hoping someone may come across them on a shipping list or be able to advise me the best place to look.

Their last name was Bishop -  and I think the first names were Frederick, Frederick and William. They came from Wellington in Somerset and were ironfounders and mechanical engineers.

I suppose they could have travelled from Bristol, Southampton or London.

I think the most likely railway was the Transandean Railway which was being built at the time so this would have meant they went to Argentina

I am also looking for their return. I think they came back separately. I think two had returned by 1891 - but one of the Fredericks is mssing from the 1891 census. He had definitely returned by 1894. The story is that he worked his way back as a cook on a merchant ship.