score:5
After some confusion, I think I've identified the misunderstanding here. @chx has already provided a good answer to the question as literally posted, but I have a feeling this might be something closer to what you want.
Crossrail's Essex branch will operate entirely over a route that already has trains. Crossrail's trains will gradually replace the existing local trains on the route, before the route is eventually diverted underground between Stratford and Liverpool Street and onwards through central London in a couple of years.
The route in question was until a couple of years back the Greater Anglia service from Liverpool Street to Shenfield calling all stations along the way (the "Shenfield Metro" service). This was taken over by the company that will become Crossrail, but in order not to tarnish the Crossrail brand (the existing trains are rather worn out and shabby, not to mention overcrowded) they are currently branded as TfL Rail. It is these services that Crossrail will replace (and, eventually, supplement).
All Crossrail trains to Essex will still be calling all stations to Shenfield (or terminating at intermediate stations in the peaks).
While the service frequency will eventually increase, this will not happen straight away. At the moment, all that is happening is that the existing, worn out Class 315 trains are being replaced with the brand new Crossrail class 345 trains. The route, calling pattern, service frequency and (likely) overcrowdedness of the trains will all remain constant until the section through Central London opens in 2019.
For this reason, I highly doubt Crossrail will provide a markedly better experience in the short term, especially if your friends are not travelling to a Shenfield Metro destination.
Upvote:2
From TFL:
From May 2017 we will gradually introduce new trains on the Liverpool Street to Shenfield route currently operating as TfL Rail.
The Sun explains it like so:
New trains will run on a TFL Rail line from Liverpool Street to Shenfield in Essex from May 2017, but this stretch wonβt be connected to the Elizabeth line for two years.
According to this forum post which quotes the @tflrail twitter account
Hi, new class 345 trains are not in service as yet they will be from 22nd May. Have a good day.