@Eggie : I m not even sure DB is running into the UK yet, but I know it has plans to. To answer your

A friend of mine who lives in England told me that sometimes on his lunch break, when he feels for good tasting fried chicken, he would board a train and in a matter of minutes he would reach Germany, cheap airline flights fares eat his lunch and he would head right back. What is confusing to me is when I looked at the map, I saw that they are separated by a body of sea water so what I want to know is how does the train line get across? Also, is it true that he can arrive there and back in limited time and is it really cost effective?
I thought it would take hours, am not much aware about it. I think currently, only Eurostar has the use of the Channel Tunnel, giving it a total monopoly on trains to Europe, with passengers changing at Brussels to reach other destinations.
There is a tunnel under the English Channel, so you can travel cheap airline flights fares by train from London to Germany (I believe you d have to change trains at Paris though). However you can t get there and back in your lunch break and it is expensive. Your friend is pulling your leg.
@Eggie , it s the same tunnel that @Smitha mentions, cheap airline flights fares the Channel Tunnel, or Chunnel . It will get you from the U.K. into France and you can take another train into Germany from there. Also, as @downtide mentions, you cannot cheap airline flights fares do that on a lunch break, the trains are fast there but not that fast.
@dabbler and @downtide I have researched it on YouTube and it was a marvelous engineering feat. Could my friend do this if he was talking about France instead? Been a long time since I had that conversation with him and may have misquoted him
@Eggie My niece has traveled from the suburbs of London to Paris and back in a day. It is about 2 and a half hours on the Eurostar each way from the center of London to the center of Paris. You can do it in a day but not on a lunch break and you could not get to Germany in that time.
Not only would it not be enough time, but in reality would it be cost effective to do a trip like that just to add choices to one s work lunch selections? Plus, since it involves two different countries, wouldn t one have to go through customs? Is someone going to pay that and take that time and effort for a lunch hour?
I would guess the probable route is London to Brussels and then into Germany. I ve taken the route before, but back then it required a transfer in Brussels to get to London. Evenso, Cologne to London was about five hours, not bad at all. Here is a map.
@Eggie : I m not even sure DB is running into the UK yet, but I know it has plans to. To answer your other question about cost-effectiveness, I think virtually every HSR line in Europe cheap airline flights fares has proven to be profitable.