When passenger trains have the heavy and sturdy engine car in front they are far more safe. In the event of a crash the weight of the engine usually allows it to plow through any obstruction protecting the passenger cars behind it. When the engine is in the rear of the train a relatively light passenger car is in front and is much more likely to derail and injure or kill passengers because it is easier for it to be lifted off the tracks. In recent deadly rail disasters the engines have been at the back of the train.
It takes time (and therefore money) to move the engine from the back to the front but it will save lives.