Performing Tahajjud Salaah when one is on safar
Q: We understand that when a person undertakes a journey for a distance of more than 48 Miles/77 km from his city of residence, he is required to offer only 2 Rakaahs of Fard Salaah, if offered alone, up to 19 days of his stay in another city, as confirmed in Sahih Hadith. But, for those who regularly offer Tahajjud Salaah, should they continue offering Tahajjud Salaah for those 19 days while they are in a state of journey to another city? Or is there an exception for them. Please clarify.