There will be a full service operating on Monday/Tuesday for the East London Line routes. However, it's safe to say expect short notice changes or cancellations if there's any infrastructure issues due to the heat.
Romford-Upminster: No Service
West Anglia: 30-40% reduction in services
GOB: Full Service
NLL: All Richmond Services Withdrawn, Clapham-Stratford Only
Watford DC: Blanket Speed Restriction of 20MPH For Entire Route/2 Trains Per Hour
ELL: Full Service