Yesterday (Sun 29/10), being in the vicinity of Eccles station at the relevant time, I was surprised to find the 1402 departure for Manchester Airport (1315 ex-Lime Street) formed, not of the usual 319, but of a double Pacer, which did seem consistent with the set being 12 minutes behind schedule. The set was comfortably full, which is what I would have expected, loadings on Sundays on the Lime Street to Airport stoppers being healthy, not least because many of the passengers who would, any other day of the week, have travelled on the 'semi-fast', need to be accommodated.
The following journey (1415 ex-Lime Street), was 16 minutes late at Eccles, and formed of a single pacer. Needless to say, passengers were standing all the way down the aisles.
At that point I noticed a scrolling message mentioning an earlier train failure. Checking it out, it seems that the first journey of the day Lime Street to the Airport stood for 59 minutes at Broad Green, and for a further 18 minutes at Roby. I can only presume that the unit involved was 319374, since I can't see any sign of a unit recovery/substitution. The said unit then continued on the service for the rest of the day, the only subsequent blip being a wait of six minutes at Oxford Road on the immediately following return journey.
The double pacer started out as the 0859 Manchester Piccadilly to Liverpool Lime Street. The first Sunday journey from Piccadilly/Airport (the originating point regularly changes between the two) is diagrammed for a diesel, which, after arrival at Lime Street then usually goes on to CLC stoppers. Yesterday it couldn't (the CLC line was operating from Hunts Cross) so, yes, I can see the point, keep the diesel on Lime Street-Airport all day, it saves leaving a 319 overnight at Lime Street (although that does happen most nights of the week), and solves the problem of what to do with the diesel. All the same, I think, had I been forced to use a diesel, I would have been inclined to use something as closely as possible resembling a 319, e.g. a double 150/2.
The single Pacer wasn't brought into play until 1420 (operating a slightly delayed 1415 Lime Street to Airport). It was 16L arriving at the Airport, 5L departing, and 19L arriving back at Lime Street (at 1721, so a departure would have been a greater amount late than the previous time around). In the event, the next two round trips were cancelled.
All in all the following journeys were cancelled.
0915 Lime Street to Manchester Airport - explanation given, problem with the traction equipment.
0946 Manchester Airport to Lime Street - explanation given, problem with the traction equipment.
1115 Lime Street to Manchester Airport - explanation given, problem with the traction equipment.
1246 Manchester Airport to Lime Street - explanation given, problem with the traction equipment.
1715 Lime Street to Manchester Airport - explanation given, problem with the traction equipment.
1846 Manchester Airport to Lime Street - explanation given, problem with the traction equipment.
2015 Lime Street to Manchester Airport - explanation given, late arrival of an inbound service.
2146 Manchester Airport to Lime Street - explanation given, late arrival of an inbound service.
So that was eight journeys cancelled, out of a scheduled total of 31.
Note that there wasn't much point in running an 0915 journey Lime Street to Manchester Airport, since at 0915 the line was still blocked at Broad Green. Also, the delayed 0812 journey effectively covered, from Roby onwards, the departure times of the 0915, so, to passengers waiting at points Roby onwards, it was effectively the 0812 journey which had missed. (319374 remained on the later timings for the rest of the day).
I'm not particularly blaming Northern for a vehicle failure, but I think I'm more than a little critical that it took from 0940 (when any line blockage was cleared) to 1420 before there was a full complement of trains operating the Lime Street to Manchester Airport service. Whether there was, even then, is arguable. As to what happened after 1715, you get the feeling that everyone just decided to 'give up'.
TPE also seems to have had a bad day, with several cancellations, including that of the last journey of the day Manchester-Scotland (1858 Manchester Airport to Glasgow).
Post Script: I've sort of lost track of how many 319s Northern currently has available for service, but I presume that it's over 20. Of those, I reckon 319374 was the only one in use yesterday.