Is the prayer of the questioner valid after she combined the Asr and Dhuhr prayers due to the train schedule, and delayed the Maghrib prayer until she arrived home, so she prayed it before the Adhan of the Isha prayer, given the train's delay?

If the train's arrival destination is your place of residence, or you have established a residency there that nullifies the ruling of travel, or you have a wife with whom you have consummated the marriage, then it is not permissible for you to combine the 'Asr prayer with Dhuhr. You must perform it at its proper time before boarding the train. If the time for 'Asr passes you, pray it on the train shortened, and then repeat it afterwards as a precautionary measure. However, if the train's arrival destination is not your hometown, and you do not have a residency there that nullifies the ruling of travel, nor a wife, then it is permissible for you to combine Dhuhr and 'Asr by advancing the 'Asr prayer (jama' taqdeem), and Maghrib and 'Isha by delaying the 'Isha prayer (jama' ta'kheer) if the time for Maghrib passes you while traveling, provided that the journey is a journey of shortening prayers (83 km or more). If you arrive at your hometown before the 'Isha prayer time begins, then you must perform the Maghrib prayer at its proper time after your arrival. It is permissible for a traveler to combine two prayers, whether he is on the move or has disembarked.