The TS statement indicated that the cascade of DMU 170's from the Bathgate electrification combined with the Newcraighall units would be sufficient to serve the Borders Rail Link.
TS/FSR also want to strengthen services to Kilmarnock, and across the Shotts line (Caledonian express) as well as increasing capacity on Fife services.
Most of this will come about by electrification elsewhere and unit cascades, reading their 10 yr plan. i.e. 4car units for Ayrshire releasing 334 units for the Airdrie / Bathgate services; electrification or E&G va Falkirk allowing release of class 170 units to strengthen Fife, Aberdeen and Central Scotland Commuter journeys (including East kilbride & Kilmarnock).
The Kilmarnock services are to be strengthened to 4-car services throughout the day and 6-car services at peak periods
However, there are restrictions at some platforms which need to be addressed first, and this is also the same reason as to why Class 170s were not used on the route
The Class 158s currently "allocated" to the Edinburgh - Bathgate service will be cascaded to the Edinburgh - Dundee and Edinburgh - Shotts - Glasgow routes, releasing further Class 170s
Details for an EMU order are due by March 2008
It is expected that the order will be for 38 four car EMUs, for use exclusively on the Ayr Line and North Clyde routes (which will extend between Dalmuir, Airdrie, Bathgate, and Edinburgh)
This will release the Class 320 units, allowing the Class 314s to be returned to RoSCo
However, due to increased pressure on the Edinburgh - Glasgow routes, it has been suggested the EMUs may be the first in Scotland with First Class
There is also a proposal to build a new chord between the Cumbernauld line and Springburn (Queen Street Low Level) line, freeing up more paths for Glasgow - Falkirk services