The development comes amid the two-day closure of the Pakistani airspace.
The Green Line train from Islamabad to Karachi, which typically sees 280 passengers a day, was at full capacity in the last week, with 324 seats and two to three additional coaches.
Pakistan Express and Tazgam also brought passengers in additional coaches, while the Quetta and Mehar Express trains also carried more travellers than usual.
Five Lahore-bound trains left the city with all seats occupied, forcing Railways management to increase the number of coachers.
A senior Railways official said 70 per cent of seats are usually booked on Lahore-bound trains every day, but in the last two days, 100 per cent of the seats had been booked a day earlier.
Meanwhile, high-level meetings were held by the aviation authorities and airlines' managements on Thursday, reviewing the situation, particularly the handling of thousands of air travellers who had been affected.
The Civil Aviation Authority (CAA) had briefly opened the airspace on Thursday at 4.10 p.m., allowing the aircraft of foreign airlines parked at Allama Iqbal International Airport Lahore and Bacha Khan International Airport Peshawar to fly back to their original destinations carrying their crew members only.