Both parents commuting to London - how do you find it?

[LadyEastEnd]

We are planning the move to Chelmsford in the next 12 months. However as we are both starting new jobs in central London in the next month or so it is possible that we will not want to change again when we move. We had planned to have at least one of us working in or around Chelmsford but we are not sure if it will be possible now due to a considerable salary drop for me and lack of availability of opportunities for my DH being the main considerations. We have two school age children and one toddler so they will be in after-school childcare and nursery/childminder. We will both probably work full time also. The commute from Chelmsford into central London is 30 minutes, so not too bad and we will work within 15 minutes walk of the station. My main concern is the reliability of trains and what to do if there is a problem on the line that stops us getting to DCs. I am also concerned about what to do if there is an emergency where we need to get to DCs quickly. Currently I work within twenty minutes door to door from home and DC's school.