I figured the first car had the least velocity and least tension, just because it seems the last car has the most velocity. Least bewteen the last car and the caboose. The tension would be the greatest between the locomotive and the first car because the locomotive is pulling the entire mass of all the train cars. However the tension between the last train car and the caboose would be the least because the last train car is pulling a lihter mass, only the mass of the caboose. Tension is a force and the lower the mass at a constant speed the less the tension.
Tension is related to the weight and the acceleration.
The locomotion is pulling the whole train, giving it a higher weight, and therefore more tension. The last car is pulling only the caboose, a lesser weight, making the tension in the couplings between them less. Can't be determined from the information given. Since we do not know the mass of each of the train cars, we cannot determine the tension between the train cars. We have no way of knowing whether the masses of the cars are equal or not, thus we cannot draw a valid conclusion with the data provided.