Abu Nu'aim has in his Mustakhraj of Muslim, "While on a journey, if the sun declined he (ﷺ) used to pray Zuhr and 'Asr together and then continue his journey."

وَلِأَبِي نُعَيْمٍ فِي

مُسْتَخْرَجِ مُسْلِمٍ

: { كَانَ إِذَا كَانَ فِي سَفَرٍ, فَزَالَتْ اَلشَّمْسُ صَلَّى اَلظُّهْرَ وَالْعَصْرَ جَمِيعًا, ثُمَّ اِرْتَحَلَ }