Some might remember and noticed that the DTG route London - Peterborough has included a second track line that runs over Hertford. Buth this part was never finished, there was only track and no scenery. 
.... UNTIL NOW... 
Since today the Freeware "The Hertford Loop v1" (by Twistedredblack) is published on https://alanthomsonsim.com/?page_id=2266
The Hertford Loop runs from Alexandra Palace to Stevenage via Enfield and Hertford. Something about 24 miles with 11 stations, double track and electrified. But you can drive here the whole ECML South between Peterborough and King´s Cross too. 
Included are two quick drives (covers only the Hertford Loop section) and 3 scenarios.
The Bad thing - a lot of Payware is needed. The Good thing: the Freeware can be deinstalled easily manually, because you have only one asset folder in the freeware route. So there should be theroetical no (less) impact to other routes if you delete it. 
Following Payware is needed:
- ECML London - Peterborough
- WCML North
- Liverpool - Manchester
- North London & Goblin Lines
- Portsmouth Direct Line (Waterloo - Portsmouth)
- Settle to Carlisle
- North Wales Coastal
- GEML London - Ipswich
- SWML Southampton - Bournemouth
Additional the:
- Wherry Lines [Armstrong Powerhouse]
- Just Trains Common Library (should be included in JT-Routes since Edinburgh - Newcastle)
- WCML "The Missing Link" [available on ATS too, but for this you need a one-year-subscription because its premium content]
For scenarios further rolling stock are needed.
. Solangsam sollten doch die meisten nach mehreren Strecken wissen, was sie bei RSSLO (und bei DTG, bei JT, GB...) erwartet! So schlimm sehen die Gleise erstmal auch wieder nicht aus. Zumindest nicht verglichen mit deren frühesten Werken.