*without* entering into a debate if the Elizabeth Line counts as main line or a tube / metro, it has a 1:27.
1:27 is from Pudding Mill Lane portal west to around about Eleanor Street.
1:28 either side of Woolwich station.
1:30 is the maximum at other places (Royal Oak portal, Victoria Dock portal, North Woolwich portal, possibly other).
_
Thameslink core has two 1:29 sections not one.
Between CTK and BFR as already posted, and west of ZFD where the Thameslink tracks dive under the Met.City.
I beleive the CTK/BFR 1:29 came into being when the BFR / CTK section 1990 rebuild and realignment, and was 1:30 before rebuild which, despite the years since, may account for 1:30 still appearing in places even now. (1:30 might be an average, but that depends on how far either side you measure from.)
The ZFD 1:29 has always been that, but no-one ever seems to mention the actual gradient despite many references to the one time kettle freight banking operation through there.
_
For reference, here are the LU gradients greater than 1:30
BUT be aware some of these are very short - indeed more than a couple of them are only approximately the same length as the type of train working that line. But nonetheless important, a train still has to be considered to power or brake or be held stationary at such a location.
Also all of these are deep tubes ,except the Earls Court > West Ken. route in that direction only.
Northern | NB | 1:19 | Kennington | route via Bank
Northern | SB | 1:24 | Borough
Central | EB | 1:25 | Oxford Circus
Central | WB | 1:25 | Holborn | to TCR in section
Central | WB | 1:25 | Notting Hill Gate
Northern | NB | 1:25 | Oval
Central | EB | 1:26 | Marble Arch
Central | WB | 1:26 | Bank
Central | EB | 1:27 | Bond Street
Central | WB | 1:27 | Bond Street
Central | WB | 1:27 | Queensway
Central | EB | 1:28 | White City to Shepherds Bush | in section
Central | EB | 1:28 | Chancery Lane
Central | WB | 1:28 | St Pauls
Central | WB | 1:28 | Tottenham Court Road
Central | WB | 1:28 | Oxford Circus
Northern | NB | 1:28 | Tooting Broadway
Northern | NB | 1:28 | Clapham North
Northern | SB | 1:28 | Tooting Bec
District | WB | 1:28 | Earls Court | towards West Kensington
Central | WB | 1:29 | Lancaster Gate
Central | WB | 1:29 | Holland Park
Northern | NB | 1:29 | Angel to Kings Cross | in section
Northern | NB | 1:29 | Balham
Northern | NB | 1:29 | Clapham South
Northern | SB | 1:29 | Old Street
Northern | SB | 1:29 | Bank
Northern | SB | 1:29 | Balham
_
The LTSR built the Whitechapel and Bow Railway jointly with the district line and the eastbound gradient from Bow Road to Bromley is 1:28 which was originally worked by steam.
It’s now part of the District/Hammersmith.
1:38.
At least today.
I have seen it stated before as 1:28, and when I looked into it, Bow Road / Bromley is, today, 1:38/1:39/1:40 both roads, for about 300 m only. That is on current data.
I have no idea if something has been rebuilt to have changed things.
Suggest if not rebuild then there has been a typo in older sources; there would have to be both multiple different typos and multiple drawing errors for the data source I used to be not right.
