Tipping on the Canadian. AMerican or Canadian dollars?

I am looking forward to my September trip on The Canadian. I will be in sleeper so my meals will be included.

However, I will be tipping in the diner. Any thoughts on whether most Americans use American dollars for that or Canadian. Whch is preferred?

And, for that matter, what about taxi cabs? Does it matter to the avrage taxi-driver?

Tips in U.S. dollars are welcomed by everyone in the hospitality business. After all, the ratio of U.S. vs Canadian currency means that the recipient of the tip is getting a bonus.

As far as spending U.S. currency in Canada, although it is accepted at a lot of establishments, it is not legal tender and you will often receive change in Canadian currency, simply because a lot of businesses don't have much U.S. cash on hand. Also, you may not get a favourable exhange rate. Businesses that deal with a large number of U.S. tourists (generally those close to the border) will give a better rate and will probably have change on hand. For the best deal, exhange your money at a bank or use a credit card.

Enjoy your trip on the Canadian; it's a great experience.