Question about travel time

OK, I'm not Norwegian, but was born in Minnesota and we have a great many Norwegians there, so hopefully that will make this alright. My great-grandparents (from Poland) arrived in Glasgow from Hamburg sometime after their ship the Flamingo sailed from Hamburg on April 13, 1881. The information I have is that they were sailing to America via Glasgow and Hull. I think that they actually took a train to Liverpool and shipped out for New York from there. I'm trying to determine how long it would have taken them to travel from Hamburg to Glasgow. Also, if they would have had to spend a few days between arriving in Glasgow and traveling by train to Liverpool. I've been searching for the ship they took to America for over 15 years and was just lucky enough to find them on the Hamburg Indirect index. If anyone has a clue as to approximately how much time it MIGHT have taken them to travel from Glasgow to Liverpool it would help me narrow down my search. I'd appreciate any information or suggestions. Thanks, and I do like lefse.