Probability in monopoly 
Based off of this classical monopoly board, my friend told me that it is better statistically to get 3 properties because you are more likely to land on the properties because they are close together. Because the properties are close together, it means that the probability of you landing on them is higher.
What I said is statistically it is better to get the railroads because there are 4 railroads on the board.
So the probability of landing on a railroad every time going around the board is 4 / 40 which is a 10% chance.
And the probability of landing on the 3 properties right next to eachother is 3 / 40 which is a 7.5% chance.
There are other factors involved like you have to roll 2 dice. This means 6 7 8 are the most common dice rolls, with 7 being the most popular.
What I want to know is, statistically through the course of a game where you might go around the board 20 - 30 times, is it more likely for you to land on the railroads or land on 3 properties (such as orange or red).

Your real mistake here is in assuming that your chance of landing on any particular property each time around the board is $1$ in $40$, which is where you got your 10% and 7.5% chances for landing on a railroad or 3 properties, respectively.  You seem to be saying, for example, that in a game where you go around the board 20 to 30 times, you only expect to land on a railroad 2 or 3 times.  I'm sure you'll agree, that's way too low!  
