I think what you are talking about is what is known as the "Indirect route". This was used by a lot of people because it was cheaper than getting to Bremen, Hamburg, Le Havre and taking one of the regular Atlantic crossings. The people would have one ticket which brought them from Russia to Libau (today Liepaja in Latvia), Germany, possibly Stettin or Hamburg by train, then a trip to the East Coast of England, Hull or Grimsby - the traffic to Grimsby was so great they had a separate railway station just for emigrants in transit!, then by train across England, mainly to Liverpool, but also Glasgow or Leith, then on to North America, also to other ports, Southampton for South Africa, London for Australia, New Zealand but the North American traffic was the heaviest. Slower, smaller but cheaper than the big ships on regular runs across the Atlantic. The Wilson Line were the main movers from the Baltic/Germany to Hull/Grimsby. Try googling "Indirect route" and Wilson Line, you will find quite a bit of information.