Haha looks like someone is posting their homework in sajha. I would have done it for you but I choose not to. ER diagram is the basics of understanding DBMS. If you don't understand ER, you will basically do not understand the logical model or the physical model, schema and anything that follows after it. At least if you know how to draw ER diagram, you can generate all other models using power-designer or othe automated software. So, pour in some efforts now and do your homework. Believe me you wil thank me later

Just to give you a hint.. Separate the main entities and their attributes  from the requirement and go from there.

nice username!! ^^

Thanks!. Actually, that is what I wanted to confirm with the experts.I just want to know how many entities can I make out of it . I can figure out the attributes myself. But figuring out the entities, relations and also one to one and many to many relationships are some difficulties I am facing. Its not that I am not trying and letting others do it. I am just asking for help if I can get any to figure out different entities in this case and how to show the relations between them.
Thanks!

If i remember this still correctly from my college days...
I think our professor told us the easy rule -
"Noun" are entities and 'verbs' and 'adverbs' are attributes.....

May be I m wrong, but this might be true in most cases...

 Stupida is right
 The general rule of thumb is nouns are entities and verbs/adverbs are attributes. There may be some exceptions to this rule according to your requirement. After you create boxes with entity as the title and their attributes( right below it),  the relationship and cardinality should be pretty easy. Cardinality is the maximum and minimum constraint you put on the relationship. The main point is to consider the ramifications of those cardinalities.
                              Lets say you have a professor entity on left side and the students entity on the right side. So when you do cardinality, you place yourself on the professor box and look towards student, then ask how many students can a professor teach in a class? If the business rule says, there has to be minimum 10 students to offfer a class and max 32 students per class, the cardinality is (10,32).
                           Then you place yourself in the student box and look toward professor then ask how many professors teach a class of students. If your answer is 1, then the cardinality is 1. The ramification is when you offer a class, it must have a professor. DBMS does not let you leave the professor field null.
                              Lets say there is another entity called course. A student may be enrolled in one or more classes. Look at the verb may be. This means a student can take zero or more courses. It you put the (1,n) as the cardinality here, it means each student must have taken a class which creates some problem later. So the cardinality should be (0,n). 
                          Hope this clears it for you.

Small hint: Entities can be Train, Employee, Station, Line(lineId, linename, trainstartlocation, endlocation, distance, trainid).

Thank you so much for taking time to explain things...If you can help me telling all the entities and how to connect between them in this particular example..it will be helpful...
Thanks!