Same Train - Different Price on different country site, Why

Good question. Maybe it has something to do with government subsidies? What else?

A perfect example is the difference between Czech Rail and German Rail fares. Bayerisch Eisenstein and Zelezna Ruda share a station building on the Czech-German border, but a ticket from that station to Pilsen, on exactly the same train, costs 4,98€ (137 Czech Koruna) from Czech Rail, but 14,80€ from German Rail.

On the other hand, with a Bayern-Böhmen-Ticket, you can go from ANYWHERE in Bavaria to Pilsen for 26€, single, to 31,50, (15, 75€ ea for two people).

Are you sure? I would expect SBB to quote in CHF, not Euros.
When I tried sbb.ch, it showed CHF 194.00 = € 160. trenitalia.it showed €135.80. Admitedly a difference, but less than you said. I would just go for the cheaper price.

Oops Swiss isn't on the euro. I remember that from the beginning of rick's swiss book.

I just wanted to make sure if I go with Trenitalia that there wasn't say a tax or something we pay someplace in Switerzland.

I suggest you post on the Train Travel Forum on Trip Advisor. There are people on the site who are also experts on European trains who may be able to help you get the best fares.
Train Travel

189 CHF is about 155 or so Euros? So there is something else going on...maybe some tax or surcharge? Just guessing here but it isn't a straight currency conversion issue.

The ticket price Trenitalia is showing you is a "Cartafreccia Senior" special. Unless you have a Cartafreccia card (unlikely, pretty much only for residents of Italy) you cannot get the 135.80 euro price. Only full fare 2nd class tickets are available for the Rome-Milan leg at 86 euro. The EC portion from Milan to Luzern is 67 euro. 67 + 86 is 153 euro, pretty much what SBB is quoting. However, there are still economy 1st class tickets available for 79 euro, I just don't know if there is a way to split the ticket for 1st class to Milan and 2nd class to Luzern without buying separate tickets. If you did that, I assume you would loose protection on the continuation to Luzern if the Rome train was late.
On the trenitalia site, click on "select" to get all the price levels available and you will see what I mean.

If you cannot show a valid Cartafreccia when the conductor checks your ticket here is what happens:

"In case of failure to present the Carta Freccia, you have to pay the difference between the amount paid and the price of the used train - one way ticket Base full price - plus an extra charge of 8 Euros per traveller. However, in the experimental stage and until further notice, the traveller can obtain the annulment of the regularization given in the report issued on board, exhibiting, within 3 days of the notification, at any Trenitalia's ticket desk from, the Carta Freccia valid at the time of regularization and paying 5 ? for administrative expenses. In this case, nothing is due on board."

Sam probably has the explanation in this case, but sometimes it just happens with international trips. Either one country does a specific ticket deal that no other country does (eg the very cheap tickets for travel from London to German cities via Brussels that are only available from DB), or one country's site sold out of its allocation of cheap fares before the other.

Robert, all websites giving prices (train, airline, hotel) give the currency with the price; either with the currency symbol: €, £ etc., or by using the standard 3-letter abbreviation: EUR, GBP, CHF, DKK etc.
Airline websites usually quote in the currency of departure. If you look up a flight from London to Paris it will quote in GBP, if you look up a flight from Paris to London it will quote in EUR.

You need to look at what currency it says on the site, not just the numbers, or what some guide book says.

The full fare Trenitalia price is 153 euro, equivalent to $193 US as of this morning.
The SBB fare is quoted is 189 chf, equivalent to $198 US as of this morning. (It just keeps getting cheaper!)
Buy from Trenitalia and save $5. SBB is adding a small fee for foreign currency conversion since the Rome-Milan leg is only available in euro through Trenitalia. Trenitalia can sell both legs as the Milan-Luzern leg originates in Italy.

Different countries have different train prices I think probably based on standard of living among others. The good example is price of ticket from Zelezna Ruda to Prague as Lee pointed if you buy it from CD (Czech Railroad) or DB (German Railroad). If the Czech price would be the same as the German one, the trains in Czech R. would be almost empty because very few Czechs would be able to afford to pay that price. I noticed that the most expensive trains are in Scandinavia, Great Britain, Switzerland, less in Germany, even less in Italy and the cheapest are in former communist countries (but price is going up there every year).

Thanks All. This is some good information.

This is more or less for the same reasons you can have a code-share flight (same airplane on same time) whereas you pay 400 in one airline or 600 in other airline, both sharing the flight and each having its own code, marketing, FF plan...

International trains operate the same way, at least the long distance ones.

This happens often if you quote prices for travel on Eurostar and its combinations, on ICE trains in and out of Netherlands, on the new international trains between Barcelona and Paris etc etc

If you want to understand Italian train "logic," pick up Tim Parks' latest book