As a day one acela owner I can give you my experience and opinion.
1 the problem with the draw bar theather is a 3 piece set that over time gets lose leading to 90% of the problem I took every car apart to lower the trucks to take the draw bar out take small screw out and glue the 2 section that make up the draw bar makein it one this will fix the communication issue from the wierless teather. It will keep it strait .
2 powered unit non powered unit the hubs that hold the wheels some have zink rot my original one had 6 bad out of 16 to replace you will need to buy the dummy truck at a cost of $91 with tax and shipping this is only if th have a bad hubs .traction tires are not easy to change .
3 updated pentografs boards if not upgraded to new ones will cost you $100
4 no grades or s turns but that is if you dont modification on the draw bars
5 the set is beautifull if you can modify the draw bars that will take time and work
