sentences:  Economic difficulties imposed by World War I meant that the dining cars were withdrawn in 1917 and never returned; instead, an extended stop was made at Frankton to allow passengers to purchase a meal.By 1917, the service ran to a schedule of seven hours and motive power was provided by the A class, but a few months after the removal of the dining cars, manpower shortages caused by the War led to the "Rotorua Express" being combined with the "Thames Express" for the run between Auckland and Morrinsville, where they were split to run to their separate termini.This combined service required 7 hours and 40 minutes to reach Rotorua, in part due to the shunting required in Morrinsville.