I still think you're under the impression that there's a period when almost all lines can have smaller units than in the morning and evening peak periods. That may be the case with 333s in West Yorkshire, it's also the case with 323s on Manchester to Alderley Edge/Crewe. From experience it's not uncommon for 80-90% of the seats to be taken on a train in the off-peak period. Hyperthetically if you ran single 153s on Chester-Manchester, Manchester-Liverpool and Hazel Grove to Preston at off-peak times instead of 2 car pacers or sprinters you'd have as many crowding problems at off-peak times as at peak times.
If 142s could be the best solution then why is a modified 170 being built for Birmingham, rather than something similar to a 142?
At a guess, the reason for building a modified 170 rather than an all new design similar to a Pacer, is one of cost. The development costs of building the 172s is minimal - they should be fairly reliable and use proven technology.
The difference 25 years ago was BR needed to replace a lot of 1st gen DMUs and fairly quickly. Consequently different designs were tried for different types of route - and you ended up with the Pacers and Sprinters.
Arguably, the "lightweight" solution the Pacers provided has been developed into the PPM which for some uses makes complete sense.
Whilst unpopular, the Pacers do actually do a reasonable job. OK there are overcrowding issues - but that's not confined to Manchester or the North - take a look at the London area where most commuter lines are suffering from overcrowding.
And in terms of rolling stock - some of the oldest and hardest worked units on the network are in use around there (313s, 315s, 317s, 455s) all of which pre-date either the Sprinters or Pacers. And the London area has always had some of the oldest stock in use - in the 00's it was the last of the 'slammers' on the Southern area and the Thumpers, in the 90s it was the 312 and 310s on the GE / LTS and in the 80s there were the EPBs, 117s on the Western, 115s out of Marylebone. The Pacers may be old, but there are older units which are probably in greater need of replacement.
And in terms of rolling stock - some of the oldest and hardest worked units on the network are in use around there (313s, 315s, 317s, 455s) all of which pre-date either the Sprinters or Pacers. And the London area has always had some of the oldest stock in use - in the 00's it was the last of the 'slammers' on the Southern area and the Thumpers, in the 90s it was the 312 and 310s on the GE / LTS and in the 80s there were the EPBs, 117s on the Western, 115s out of Marylebone. The Pacers may be old, but there are older units which are probably in greater need of replacement.
And in terms of rolling stock - some of the oldest and hardest worked units on the network are in use around there (313s, 315s, 317s, 455s) all of which pre-date either the Sprinters or Pacers. And the London area has always had some of the oldest stock in use - in the 00's it was the last of the 'slammers' on the Southern area and the Thumpers, in the 90s it was the 312 and 310s on the GE / LTS and in the 80s there were the EPBs, 117s on the Western, 115s out of Marylebone. The Pacers may be old, but there are older units which are probably in greater need of replacement.