The slow lines via WGC are mainly 75mph maximum.
maybe 90mph would be useful for some services especially when routed on the fast lines when there is disruption.
The service I use in the mornings starts at Letchworth to Kings Cross via WGC this is currently a 313, fast from Stevenage to WGC. A bit more speed would help through the Welwyn section. That train used to be a 365 which generally arrived about a minute earlier at WGC (where it waits for a few minutes).
maybe 90mph would be useful for some services especially when routed on the fast lines when there is disruption.
The service I use in the mornings starts at Letchworth to Kings Cross via WGC this is currently a 313, fast from Stevenage to WGC. A bit more speed would help through the Welwyn section. That train used to be a 365 which generally arrived about a minute earlier at WGC (where it waits for a few minutes).