At high speed, I imagine that Notch 4 applies the full bus voltage to the motors. But the gensets cannot supply as much current as a third rail supply, so the bus voltage will drop to limit the current. It might well be that the resultant power at the rail is no greater than, or even slightly less than, in Notch 3.
On level track, I would think that the 700kW 'ish net maximum (a 319 has 990kW) is probably OK for 75mph, - even with a normal full passenger load, but it might take some time to get up to that speed.
Well, 780kW total at the engine crankshafts, less the alternator and motor losses and auxiliary/hotel power. A 150 gets to 75mph quite quickly on the flat, but that has 213kW per car at the crankshaft (852kW total for a 4-car). I doubt there is much difference in the transmission losses at 75mph. The 150's Voith hydraulic transmission drives through a fluid flywheel, not the torque converter, when in high gear.
The 769s engines are rated at 390kw each maximum by the time you take in to account alternator efficiency and rectification and auxiliary uses I doubt you have anything like 700Kw available at the wheel and with dc motors then not over a very wide speed range.
The 319 motors are continuously rated at 990kW, that's how those motors are rated. If the two gensets plus cabling and electronic traction control losses take the maximum 390kW of the engines down to 700kW, that's what the motors get in that mode. The torque of the motors is controlled by the electronics, but the power is still whatever is input. As a comparison, the power at the wheels of a 4-car 150 consist is something less than 4 x 210kW (allowing for hydraulic and mechanical transmission losses but varying greatly depending on engine speed vs wheel speed) spread over 8 axles.
700kW of electrical power to the motors does not equate to 700kW at the rail. The motors have resistive, magnetic, windage and friction losses. The 319 traction motors would have been designed to optimise performance, size, weight and reliability. Efficiency would have been less important in the 1980s, with plenty of cheap power available from the third rail or OLE. I do not have the figures, but the motor losses might well be as high as 10% at 75mph.
not to mention it would free up diesels from the Stalyvegas to Southport (obviously the Alderley Edge should run Sundays too even if only 2-hourly, however that's for another thread).Why? Southport - Alderley Edge is of course not a required connection any day of the week, but is there not the capacity on Crewe services that there is routinely overcrowding north of Alderley Edge on Sundays?Maybe they should be used on Sundays too because they seem to have reliability problems Mondays as demonstrated in the past couple of weeks. Seems as though resting them a day does them no good
I’m not sure if it has only been in recent weeks but reliability has definitely since they entered service. I haven’t been going on them as often this year though.
Other than cancellations which would have been equally possible for booked Sprinters, have there been any more failures in service that made their introduction catastrophic or not?
The 769s should always be in Diesel mode for part of their diagrams…
Why? Do Piccadilly drivers not normally go past Bolton?
Almost correct. As the 769s operate Southport to Alderley Edge/Stalybridge and only Wigan and Vic drivers sign to Southport, Piccadilly drivers only drive them to/from Alderley Edge to Manchester Oxford Road. So the vast majority of the time they are in electric...
From December these Oxford Road crew changes will be eliminated, as there are to be separate Southport - Oxford Road and Piccadilly - Alderley Edge services. This should improve Castlefield corridor performance significantly.
As I 769 driver, I know that
So who drives the Blackpool North - Hazel Grove/Airport services past there? (I know these are pure electric)
Admittedly this sounds favourable operationally if drivers only sign as far as Oxford Road, minus the need to foul all lines to reverse out of the bay, which damages Castlefield performance quite significantly, but it’s not sustainable since it doesn’t serve the fundamental need from Southport/West Lancs passengers for a service at least as far as Piccadilly.
It serves that desire fine, because changing at Oxford Road is extremely easy, so anyone who wants to go to Piccadilly can do that. Saving a half-minute walk for people from a provincial town 30 miles away is not a reason to hold up one of the country's most congested rail corridors with unreliable rolling stock and crew changes.
If the next Piccadilly service leaves from P3 then it is a lot more than a 30 second walk. It would be advisable and much more pleasant to change at Deansgate if trains stop there or even Salford Crescent than attempt to change at Oxford Road.
Blackpool/Hazel Groves can be worked by any of:
Almost everything to Piccadilly departs from platform 4. In fact, I can only see four services today that have used platform 3; none of them were booked to do that, and on all but one, an alternative was available from platform 4 no more than 5-10 mins later.
