Is there any reason why the 5 car sets can't have extra cars added while we are waiting for all the longer sets to be commissioned, even if that does prolong their introduction?
I understand that the units' s/w is set up to allow this.
OTC
How would that work? The project is already well over budget and where woud they go after that time? They would only length them if it was permanent, and the five cars are going to run solo frequently in the new timetable.
GWR▸ (it comes as a surprise) do have a plan which they believe will work. We will have to just wait and see.
This all depends - on the meaning of a bit of the requirement that has always puzzled me.
3.3 Unit Formation and Length
TS1829 IEP▸ Units must be equipped with a Driving IEP Vehicle at each end and allow the IEP train be driven in either direction from each Driving IEP Vehicle.
TS223 IEP Units must be able to operate within the following length constraints:
• Maximum length – nominally 312m (this is the maximum design length of an IEP Unit); and
• Minimum length – nominally 130m, where two minimum length IEP Units coupled together form an IEP Train no longer than 260m.
TS1977 It must be possible to add Intermediate IEP Vehicles to an IEP Unit subject to the IEP Unit till being no greater than the maximum length identified in TS223.
TS1979 It must be possible to remove Intermediate IEP Vehicles from an IEP Unit from any intermediate position subject to the Intermediate IEP Vehicles being removed being of the correct Functional Vehicle Type and the IEP Unit remaining at least the minimum length.
TS1980 The design of the IEP Units must ensure the time to add or remove Intermediate IEP Vehicle is minimised and is in any event no greater than 8 hours.
TS1589 With regards to IEP Unit reconfiguration it must be possible to reconfigure software and control systems within 15 minutes when Intermediate IEP Vehicles have been added, removed or replaced.
There's also this bit:
3.1.3 Flexibility
TS1578 The design of the IEP Units must ensure that the IEP Units have the flexibility to allow for train formation changes, changes of power source, and redeployment throughout their life.
The design of the IEP Units must minimise the cost and timescales to effect these changes.
TS1965 It is an essential requirement that the number of different Functional Vehicle Types within the architecture of the various trains is minimised and there shall in any event be no more
D than 13 distinct Functional Vehicle Types.
Now, the published layouts (from ages ago - 2012) did list functional vehicle types, plus a longer type code that included the internal fittings too. Traditional
BR▸ vehicle labels are somewhere between those two. Those layouts are for 5, 8, and 9 car units, which are made up as:
5: DPT1 / M1e / M3-M3e / M1-M1e / DPT1
8: DPT1 / M1e / M2-M2e / T(p) / T1 / M3-M3e / M1-M1e / DPT1
9: DPT1 / M1e / M2-M2e / Tp / M2-M2e / T2 / M3-M3e / M1-M1e / DPT1
Now, I can work out that the M1/M2/M3 are electric motor cars and 'e' adds an engine, so they are listed as alternatives. And it does appear that a Tp and a T(p) are different, as presumably are T1 and T2. So it does not look as if you can make an 8-car out of one 5 plus the middles of another; it does say that anything added has to be of the right functional vehicle type (to add).