A question on Newton's laws and tension

[Charismaztex]

Homework Statement

A railway engine pulls two carriages of equal mass with uniform acceleration. The tension in the coupling between the engine and the first carriage is T. Deduce the tension in the coupling between the first and second carriages.

Homework Equations

The Attempt at a Solution

I have tried drawing free body diagrams but have not fully understood how this problem works. I can't seem to get the correct answer T/2.


Any help appreciated,
Charismaztex

 

[PhanthomJay]

You have 2 unknowns (T_12 and a) , so you'll need to draw 2 free body diagrams, apply Newton's laws, and solve the simultaneous equations. Which 2 did you choose?