I don't normally post on this kind of thing, but only today I was thinking just this exact subject, so I think I will contribute my thoughts.
First of all: today I took my first ever ride on a pacer unit which was what prompted my thought process about a new DMU. I've been working on railways for many years, but I work on TGV and European stock (I work for SNCF), and in the UK (I'm british), I use long distance intercity services on ECML, WCML or commuter trains in and around London, so I've never stopped in natural pacer territory, just blasted on through having a chuckle at them out of the window as I pass, until today...
I took one from Sheffield to Doncaster. I wasn't supposed to be in Sheffield in the first place, but that's another story not relevant to here. A quick scan of the departure boards and the quickest way to Doncaster was leaving from platform 1. Tres bien. Off I ran with 1 minute to catch it, and saw to my horror that it was a pacer (144? Possibly? I'm sure a pacer spotter will be able to tell me). I almost thought about waiting for the next TPE or XC service, but fearing I'd be even later than I already was, I figured it was time to take the plunge and after 30 years of railway travel in Europe, there was no escaping it further, I had to take the pacer.
So what did I think? I was stuck half way between being horrified and amused. It was like watching a farcical comedy - you know it's ridiculous but you have to laugh. The closest thing SNCF have are little X2100 or X2200 units, but they at least have proper bogies. The ride was - well there really wasn't one. There are coal wagons out there with more sophisticated suspension. The performance was painful. I could hear an engine being revved to death but the scenery outside was moving, but it felt like one of those tiny mopeds that plague Paris - they sound like they're doing 100km/h, but you turn round and they're barely overtaking pedestrians. That's what it felt like on the pacer. The thing was noisy, the aisle was far too narrow, the doors were flimsy and it rattled and banged it's way to Doncaster.
I'm probably preaching to the converted here, but in 30 years, I've never come across a rail vehicle like it. So this got me thinking (and I hear that they're being phased out due to legislative issues anyway), but if normal trains were cascaded down to fill the role of the pacer (and one does have to acknowledge that they DO have a role to play in these areas where there are many stations in a small area) then what would replace those other trains.
I think the TPE units (185s) are not bad trains as an example of the "top" of this cascade, but they are for mid-distance journeys only in my opinion. No longer than an hour. I'd use them as a base for a new train that was short in formation for use in smaller stations, but had a layout that was more suitable for longer distance/duration journeys. Such as East Midlands Trains' Norwich to Liverpool service, XC's Stansted to B'ham or TPE's own Manchester to Glasgow/Edinburgh trains.
In a nutshell I was thinking (and bear in mind, this was an idle moment while my senses were being assaulted by the pacer I was on):
A 4-car DMU.
Engines - As the 185 uses. Plenty of grunt for what they need.
Speed - 160km/h. Fast enough to allow realistic timetabling on longer main line stretches, but no need for 200km/h stock. It would ramp up cost, be rarely used and not benefit the passengers.
Bodyshell - As 185s, but in stead of 1/3 and 2/3 doors, have them at the vehicle ends, with saloon doors as per long distance coaches.
Interior - Plenty of tables. Wi-fi facilities. One driving coach would be 1st class with the end closest to the 2nd vehicle of the formation to have a very small snack bar/buffet area. The remaining 3 vehicles would be standard class with a large disabled area on the other driving coach.
Then I arrived and Doncaster, and woke from the dream. Or was it a nightmare?
