Jonathan Cadwallader & Martin Jenkins are to publish a book in January 2010 covering the Merseyside electric lines. Here's the blurb.

This new book provides readers with comprehensive coverage of the Mersey Railway and Lancashire and Yorkshire network. These early electrified lines once transported thousands of commuters, workers and shoppers into central Liverpool, providing essential links with the surrounding suburbs. Within this book, a carefully selected range of colour views provides a unique picture of these two fascinating networks, with scenes of rolling stock, depots, yards, tunnels, stations, signal boxes as well as passengers. Rail enthusiasts will delight at rare scenes of the electrified Southport-Crossens service which closed in 1964, steam and diesels operating passenger and freight services over the electrified sections, and photographs capturing traffic to and from Aintree Race course and the Liverpool Exchange. Other images feature the engineering works in connection with the creation of the Loop and Link, the new electrified extensions to Kirkby, Hunts Cross and Chester, and the historic final withdrawals of the much-admired 502/503s. The earliest colour views even capture the legendary Mersey Railway stock, as well as the first 25kV electric locomotives which reached Liverpool in the early 1960s. High-quality views of Merseyside's best-loved electric railway, the Liverpool Overhead are also included. The authors have worked tirelessly to provide an excellent text, supplemented by this wonderful collection of images with detailed captions. Rail enthusiasts nationwide will be eager to glimpse the treasure trove of rare railway snapshots, whilst locals will enjoy the scenes of their beautiful city in a gentler time. This is one not to be missed.

This has always been a much neglected area of merseyside rail heritage.
Definitely one for the bookshelf.
http://www.amazon.co.uk/Merseyside-E.../dp/0711034176