1: I can't get your point. 2: 餐车 in China , this word has two difference means. firstly, big vehicles which sell a lot of food , just like train carriages, snack cars, etc . secondly, small vehicles which like a shopping cart .

Somebody has answered your 2nd question already. About the 1st question, I think this is not a completed sentence. If the context before this sentence is like "Whose book is this?". Then you can answer "这个楼的工作人员的书". In this case, it omits the subject and predicate. The full sentence must be "这 是 这个楼的工作人员的书". In some other cases if you consider the book as the subject part, you should add some other primary parts like "这个楼的工作人员的书 很有意思".

2have you taken a train? It's a cart which sells drinks,fruits,food and snacks on the train. But nowadays,it is also seen on the street.

2)has been well answered, and if you say 「這是這『層』樓的工作人員的書」 or「這是這『棟』樓的工作人員的書」 ——the former means 'this floor'， and the latter means 'this building'—— not「這『個』樓」, the meaning will be more clear and it will shows proficiency. Since you're not native speaker, I don't suggest that you use 「這個樓」in this case, so that you can notice the usage and importance of 'measure word.' But you can also say 「這是『這個樓層』的……」 「這是『這個大樓』的……」 Hope that I'm helpful to you(*●>●) Ps. 这 = 這 个 = 個 楼 = 樓 员 = 員 书 = 書 层 = 層 栋 = 棟

１正确，只不过不是一个句子。 ２餐，是用餐，卖餐的意思，车就是车，餐车就是卖饭、用餐的车。大到火车上的专门一节车厢，小到一个手推车。如果你知道“餐厅”是什么，那么就能理解“餐车”是什么了。