Re#2 There is no reason for number this to be a big problem, if the MTBF isn't increasing noticeably, it is time to look for a new locomotive builder. The passenger locomotives are being stressed by the high speeds and high daily mileage. Freight locomotives are not stressed like passenger locomotives they cover less mileage (kilometreage?) than passenger locomotive in a given time period, there is no reason to see a maintenance facility more than once weekly. Also passenger locomotives become obsolete more quickly while the nature of freight transport changes more slowly. Energy efficiency is the main reason to replace some of the existing freight locomotive fleet, along with repair costs.
Re#8 There is a strong correlation between Market Share and reliability of the service provided.
Re: point #9 The Einheitsloks were only interchangeable to a small degree, the Class 110 were 150kph w/dynamic braking, the Class 113 were 160kph (needed for Rheingold and other trains), the 139 and 140 were 110 kph, so while they could do both passenger and freight they have widely differing capabilities. I am sure you have noted the Class 189s working some passenger services for DB Nachtzug, as a current example if you accept the limitations of the freight locomotive.
The passenger locomotives are being stressed by the high speeds and high daily mileage. Freight locomotives are not stressed like passenger locomotives
They are stressed differently. Just for the slip problems discussed elsewhere, they need sand re-supply, and wheel re-profiling if there are blocked wheels. Add to that the consequences of using axle-hung motors (f.e. the bogie frame damage, hit even the TRAXX 2).
passenger locomotives become obsolete more quickly
Do they? Express locos over the past century yes, due to the continually increasing maximum speeds; but old locos (ÖBB 1042, MÁV MÁV V43.10, DB 110, 111, SNCF 8500), some with with retrofitting (ÖBB, ÖBB 1142 and 1144, MÁV V43.20 and .30) survive just fine in local service. *Lunatic*, n. One whose delusions are out of fashion.
The Austrian 1042/1142 locomotives served a long life, but the future for the 1044/1144 series has gotten a lot more uncertain, and the 1014/1114 series are about finished. The rapidly expanding demand for both passenger and freight service meant that it was hard to acquire locomotives fast enough, but it is no longer uncommon to see a Taurus lok on a stopping service now. The DB class 110 only have survived as long as they have because of the inadequacy of the former DR Class 143 loks with their 120kph top speed. In spite of the vast numbers of this model I would be surprised to see many survive to 2020, except for the few being converted to Class 114.
If the TRAXX2 are suffering bogie damage from their Tatzlager traction motors then they must have been designed by the same person who designed the axles for the DB Class 403, 411, 415, and 481 units.
Re 9: in this point, I focused on benefits other than operational. The Einheitsloks (both the steamers of the thirties and the electrics of the fifties-sixties) had a geat many interchangeable parts. In the locomotive shop, even main parts could be cycled between locomotives of different classes in revision at the same time. There have even been conversions between the 110 (originally express), 139 (mountain freight) and 140 (freight) classes. *Lunatic*, n. One whose delusions are out of fashion.
Re#9 the Br 110s were converted to BR 139s by taking bogies from retired Br 140s, which probably required modifications to the traction motor cooling ducts as the Br 140 uses a bogie with a longer wheelbase.
The death knell of the Universal locomotive was sounded by the increasing differences in the type of services they are needed for. Passenger locomotives are required to achieve higher speeds, supply electrical power to passenger cars, and operate in push-pull mode. While freight locomotives need signalling systems for multiple countries, and likely the ability to operate under at least two power systems. Trying two combine both in one locomotive will result in an unaffordable price.
