"Vehicles" reads coaches to me, so they only need 10 more units.
If you look at
http://www.dft.gov.uk/pgr/rail/pi/rollingstock/rollingstockplan?page=2 if the future Northern will be expected to give 17 3 car 323s to London Midland in exchange for '23
EMU▸ vehicles' So it looks like the definition of 'vehicle' the
DfT» use is a complete unit with however many carriages/coaches it has.
Roger Ford in his excellent analysis of the 1300 new coaches promised by the DfT in Septembers Modern Railways, confirms the cascade of 17 3 car 323 or 51 vehilces, from Northern to London Midland for Birmingham area.
However, his analysis of "new" stock for suggests Northern is down for 25 * 3 car brand new Seimens units making 75 vehicles in all. They are also down for "new" DMUS amounting to 158 vehicles. Although net Northern will get only 182 "new" vehicles, (75+158-51=182). Although apparently 182 will depend on the exact 150 cascade.
Some of the 158 extra
DMU▸ vehicles are suppose to be the first of a new generation DMUs, powered it is sugegsted by Captain Deltic "bionic duckweed", rather than 170 derivatives (172) curently on order
.
So as per the
FGW▸ cascade to Bristol area of "new" stock comprising 52 150 vehicles (2 & 3 car units) from London Overground and London Midland, Northern won't be getting 182 "new" vehicles.
The whole article is well worth reading to see how D
afT have got themselves in a complete muddle over the provision of new units and resulting cascades of still servicable units. Throughout Roger Ford refers to vehicles as being coaches rather than units.
Also as far as I can see there appears to be no sign of any replacements for the 14X units, as the cascades are counted as "new" vehicles for the receiving
TOC▸ .