# Standard Corridor

The Second Corridor (previously Third Corridor) type of railway carriage was one of the standard mid-20th century designs, and was coded SK (previously TK) by the LNER and BR, and CF by the LMS. The layout of the coach was a number of compartments, all of which were second class (known as third class until 1956), linked by a side corridor.
The British Railways Mark 1 SK was the most numerous carriage design ever built in the United Kingdom. The original number series carried was 24000–26217. From 1983, those carriages in the 25xxx and 26xxx series were renumbered 18xxx and 19xxx.
There were two variants, those built for the Midland, Scottish, and Eastern / North Eastern regions had six seats per compartment, with fold-up arm-rests which folded into the seat-back, while those built for the Southern and Western regions, with their heavy commuter loadings into London, had eight seats in each compartment, and no arm-rests. Seating was of the interior sprung bench type. Over time, some SKs and BSKs were re-allocated from other regions to the Western, who tended to try to stitch the arm-rests in the up position.
In 1985, a number of Mark 2 First Corridor carriages were declassified to become SKs. They were renumbered from 13xxx to 19xxx, putting them after the end of the Mark 1 range (19452–19560).
No carriages of this type are still in daily use on the main line network, since open saloon carriages are now preferred by operating companies. However, some electric multiple units based on Mark 1 coaches have standard class compartments, such as Class 438. Many SKs still operate on preserved UK railway lines.
Designations for second corridor carriages are as follows:
| LNER Code | Description | LMS Code |
| BSK | Brake Second Corridor | CH |
| DMBSK | Driving Motor Brake Second Corridor |
| DMSK | Driving Motor Second Corridor |
| MBSK | Motor Brake Second Corridor |
| SK | Second Corridor | CF |
| TBSK | Trailer Brake Second Corridor |
| TSK | Trailer Second Corridor |

## Livery

In 1951 the initial livery for Mk1 coaches on British Railways was crimson lake and cream with black and gold lining, and all new Mk1 SK coaches were delivered in this livery up until 1956. In 1956 the standard livery changed to maroon with black and gold lining, except for the Southern region stock which adopted an unlined dark malachite green. Western Region adopted chocolate and cream on sufficient stock to operate its named trains such as the Cornish Riviera Express and the Torbay Express. In 1965 Manastral Blue & Grey livery was introduced as trailed on XP64 stock the year before and was the network standard for over 20 years. In the 1980s the NSE livery of white with blue at window level and red stripe under was introduced for stock in the south east of England.

## Orders

| Lot No. | Diagram | Mark | Built | Builder | Qty | Fleet numbers | Notes |
| 30002 | 146 | 1 | 1951 | Derby | 180 | 24000–24179 | BR1 bogies |
| 30015 | 146 | 1 | 1951-2 | Doncaster | 40 | 24180–24219 | BR1 bogies |
| 30026 | 146 | 1 | 1951-2 | York | 82 | 24220–24301 | BR1 bogies |
| 30020 | 146 | 1 | 1952 | Ashford | 24 | 24302–24331 | BR1 bogies |
| 30007 | 146 | 1 | 1953 | BRCW | 36 | 24332–24396 | BR1 bogies |
| 30030 | 146 | 1 | 1953 | Derby | 40 | 24397–24436 | BR1 bogies |
| 30072 | 146 | 1 | 1953 | Wolverton | 10 | 24437–24446 | BR1 bogies |
| 30088 | 146 | 1 | 1954 | Swindon | 22 | 24447–24468 | BR1 bogies |
| 30070 | 146 | 1 | 1954 | York | 36 | 24469–24538 | BR1 bogies |
| 30068 | 147 | 1 | 1952 | York | 30 | 24539–24548 | BR1 bogies |
| 30070 | 146 | 1 | 1952 | York | 8 | 24549-24556 | BR1 bogies |
| 30070 | 146 | 1 | 1954 | York | 12 | 24557–24568 | BR1 bogies |
| 30070 | 146 | 1 | 1954-55 | York | 7 | 24569-24575 | BR1 bogies |
| 30057 | 146 | 1 | 1953 | BRCW | 100 | 24576–24675 | BR1 bogies |
| 30058 | 146 | 1 | 1953 | Cravens | 25 | 24676–24700 | BR1 bogies |
| 30059 | 147 | 1 | 1953 | Cravens | 20 | 24701–24720 | BR1 bogies |
| 30073 | 146 | 1 | 1953 | Wolverton | 25 | 24721–24745 | BR1 bogies |
| 30077 | 147 | 1 | 1954 | Swindon | 8 | 24746–24753 | BR1 bogies |
| 30078 | 146 | 1 | 1954 | Swindon | 42 | 24754–24795 | BR1 bogies |
| 30137 | 146 | 1 | 1954 | BRCW | 23 | 24796–24818 | BR1 bogies |
| 30153 | 146 | 1 | 1955-56 | Derby | 126 | 24819–24944 | BR1 bogies |
| 30154 | 146 | 1 | 1956 | Derby | 30 | 24945–24974 | BR1 bogies |
| 30208 | 146 | 1 | 1956 | Derby | 70 | 24975–25044 | BR1 bogies |
| 30155 | 147 | 1 | 1955-56 | Wolverton | 120 | 25045–25164 | BR1 bogies |
| 30230 | 147 | 1 | 1957 | Metro Cammell | 83 | 25165–25247 | BR1 bogies |
| 30231 | 146 | 1 | 1957-58 | Metro Cammell | 32 | 25248–25279 | BR1 bogies |
| 30494 | 150 | 1 | 1958 | Metro Cammell | 3 | 25280–25282 | BR1 bogies |
| 30349 | 146 | 1 | 1957 | Wolverton | 120 | 25283–25402 | BR1 bogies |
| 30350 | 146 | 1 | 1957 | Wolverton | 22 | 25403–25454 | BR1 bogies |
| 30356 | 148 | 1 | 1957 | Metro Cammell | 1 | 25455 | BR1 bogies |
| 30358 | 149 | 1 | 1957 | GRCW | 1 | 25456 | BR1 bogies |
| 30371 | 151 | 1 | 1957 | Doncaster | 1 | 25457 | BR1 bogies |
| 30374 | 146 | 1 | 1957 | York | 50 | 25458-25507 | BR1 bogies |
| 30737 | 152 | XP64 | 1964 | Derby | 2 | 25508-25509 | B4 bogies |
| 30426 | 146 | 1 | 1957-58 | Wolverton | 146 | 25558-25703 | BR1 bogies |
| 30685 | 146 | 1 | 1961-62 | Derby | 202 | 25704-25905 | CW bogies |
| 30685 | 146 | 1 | 1962 | Derby | 67 | 25906-25972 | BR1 bogies |
| 30719 | 146 | 1 | 1962 | Derby | 87 | 25973-26059 | CW bogies |
| 30720 | 147 | 1 | 1962-63 | Derby | 78 | 26060-26137 | CW bogies |
| 30726 | 146 | 1 | 1962-63 | York | 80 | 26138-26217 | CW bogies |

## Conversions

* In 1973-74 4 Second Corridor were converted to Class 309 TSK later become TSOL
* In 1976, 9 Second Corridor were converted to Stowage Vans 80431-80439 POT
* In 1977, 15 Second Corridor were converted to Sorting Vans 80381-80395 POS.
| SK | TSK | Diagram | |
| 26024 | 71110 | 469 | Class 309 |
| 26189 | 71108 | 469 | Class 309 |
| 26196 | 71109 | 469 | Class 309 |
| 26203 | 71107 | 469 | Class 309 |
| SK | Type | | Year | Diagram |
| 25033 | POS | 80383 | 1977 | 726A/NS531 |
| 25045 | POS | 80387 | 1977 | 726A/NT531 |
| 25047 | POS | 80390 | 1977 | 726A/NT531 |
| 25056 | POS | 80395 | 1977 | 726A/NT531 |
| 25068 | POT | 80437 | 1976 | 727A/NT521 |
| 25071 | POT | 80432 | 1976 | 727A/NS521 |
| 25077 | POT | 80436 | 1976 | 727A/NS521 |
| 25078 | POS | 80384 | 1977 | 726A/NS531 |
| 25082 | POS | 80392 | 1977 | 726A/NS531 |
| 25083 | POS | 80385 | 1977 | 726A/NS531 |
| 25088 | POS | 80388 | 1977 | 726A/NS531 |
| 25089 | POS | 80391 | 1977 | 726A/NS531 |
| 25099 | POS | 80386 | 1977 | 726A/NS531 |
| 25103 | POS | 80389 | 1977 | 726A/NS531 |
| 25104 | POT | 80431 | 1976 | 727A/NS521 |
| 25109 | POS | 80382 | 1977 | 726A/NS531 |
| 25112 | POS | 80381 | 1977 | 726A/NS531 |
| 25117 | POT | 80435 | 1976 | 727A/NT521 |
| 25119 | POS | 80393 | 1977 | 726A/NT531 |
| 25127 | POT | 80439 | 1976 | 726A/NT521 |
| 25434 | POT | 80434 | 1976 | 726A/NT521 |
| 25139 | POT | 80438 | 1976 | 727A/NT521 |
| 25150 | POT | 80433 | 1976 | 727A/NT521 |
| 25156 | POS | 80394 | 1977 | 726A/NT531 |

### Departmental use

Mk1 :
| SK | | Departmental | Notes |
| 24011 | | DB975415 | Match wagon for ballast cleaner |
| 24026 | | ADB977057 | Doncester works test train |
| 24035 | | ADB975439 | Crewe works test train |
| 24062 | | LDB975062 | CM&EE Electrification staff coach |
| 24067 | | LDB975064 | CM&EE Electrification staff coach |
| 24070 | | ADB975161 | BTU tool van |
| 24085 | | TDB977187 | Train crew training coach |
| 24119 | | ZDB975074 | Exhibition coach |
| 24134 | | LDB975065 | CM&EE Electrification staff coach |
| 24140 | | LDB975066 | CM&EE Electrification staff coach |
| 24147 | | ZDB975073 | Exhibition coach |
| 24154 | | ADB975263 | Overhead Line Maintenance Stores coach |
| 24157 | | ADB975162 | BUT Tool & Generator coach |
| 24168 | | LDB975067 | CM&EE Electrification staff coach |
| 24189 | | LDB975068 | CM&EE Electrification staff coach |
| 24274 | | ADB975801 | CCE staff & dormitory coach for ballast cleaner |
| 24308 | | DB975392 | Match wagon for ballast cleaner DR76216 |
| 24320 | | LDB975069 | CM&EE Electrification staff coach |
| 24345 | | ADB975806 | CCE staff coach |
| 24410 | | LDB975070 | CM&EE Electrification staff coach |
| 24420 | | KDB975114 | S&T cable flat |
| 24428 | | ADB977058 | Doncester works test train |
| 24429 | | ADB975904 | Overhead Line Maintenance cable flat |
| 24430 | | TDB977188 | Train crew training coach |
| 24457 | | ADB975799 | CCE staff & dormitory coach for ballast cleaner |
| 24485 | | DB975412 | Match wagon for ballast cleaner |
| 24516 | | TDB977189 | Train crew training coach |
| 24531 | | ADB975726 | Overhead Line Maintenance generator & stores coach |
| 24579 | | ADB977090 | CCE staff coach |
| 24589 | | ADB975546 | Overhead Line Maintenance cable flat |
| 24647 | | TDB975135 | Lecture coach |
| 24677 | | TDB977247 | MOD special instruction coach |
| 24679 | | TDB977248 | MOD special instruction coach |
| 24685 | | TDB977422 | Special instruction coach |
| 24745 | | KDB975106 | S&T cable flat |
| 24752 | | ADB975440 | Crewe works test train |
| 24766 | | ADB975732 | Overhead Line Maintenance stores & roof access coach |
| 24796 | | ADB975802 | CCE staff & dormitory coach for ballast cleaner |
| 24815 | | ADB975803 | CCE staff & dormitory coach for ballast cleaner |
| 24841 | | TDB977497 | Special instruction coach |
| 24849 | | ADB975925 | Overhead Line Maintenance cable flat |
| 24857 | | TDB977498 | Special instruction coach |
| 24858 | | ADB977059 | Doncester works test train |
| 24870 | | ADB975441 | Crewe works test train |
| 24890 | | TDB977430 | Special instruction coach |
| 24899 | | CDB977103 | EMU barrier coach |
| 24936 | | ADB975442 | Crewe works test train |
| 24972 | | ADB975805 | CCE staff & dormitory coach for single line gantries |
| 24976 | | DB975828 | Underframes used for CCE staff & dormitory portakabin |
| 24982 | | DB975379 | CCE staff & dormitory coach |
| 24990 | | ADB975926 | Overhead Line Maintenance cable flat |
| 24994 | | ADB975915 | Overhead Line Maintenance cable flat |
| 25003 | | ADB975913 | Overhead Line Maintenance cable flat |
| 25017 | | ADB975742 | Overhead Line Maintenance office & staff coach |
| 25025 | | ADB975920 | Overhead Line Maintenance cable flat |
| 25026 | | ADB975922 | Overhead Line Maintenance cable flat |
| 25038 | | ADB977320 | Crewe works diesel loco test train coach |
| 25069 | | ADB975924 | Overhead Line Maintenance cable flat |
| 25079 | | ADB975080 | BTU tool van |
| 25094 | | ADB975908 | Overhead Line Maintenance cable flat |
| 25105 | | ADB975905 | Overhead Line Maintenance cable flat |
| 25106 | 18106 | ADB977322 | Crewe works diesel loco test train coach |
| 25122 | | ADB975443 | Crewe works test train |
| 25132 | | ADB975797 | CCE staff & dormitory coach for ballast cleaner |
| 25161 | | ADB975906 | Overhead Line Maintenance cable flat |
| 25171 | | TDB977195 | MOD special instruction coach |
| 25190 | | ADB975736 | Overhead Line Maintenance stores & roof access coach |
| 25196 | | ADB975927 | Overhead Line Maintenance cable flat |
| 25205 | | ADB975930 | Overhead Line Maintenance cable flat |
| 25222 | | ADB975622 | EMU Barrier coach |
| 25226 | | ADB975722 | Overhead Line Maintenance generator & stores coach |
| 25236 | | CDB977102 | EMU barrier coach |
| 25238 | | ADB975923 | Overhead Line Maintenance cable flat |
| 25243 | | ADB975946 | Overhead Line Maintenance cable flat |
| 25262 | | ADB975712 | Overhead Line Maintenance stores coach |
| 25281 | | DB975816 | Underframes used for CCE staff & dormitory portakabin |
| 25286 | 18286 | TDB977496 | Special instruction coach |
| 25302 | | ADB975771 | Overhead Line Maintenance office & staff coach |
| 25318 | 18318 | ADB977323 | Crewe works diesel loco test train coach |
| 25326 | | ADB977319 | Crewe works diesel loco test train coach |
| 25329 | | DB975829 | Underframes used for CCE staff & dormitory portakabin |
| 25338 | | TDB977173 | Train crew training coach |
| 25339 | | ADB977151 | Crewe work test tain |
| 25340 | | ADB975903 | Overhead Line Maintenance cable flat |
| 25343 | | ADB975798 | CCE staff & dormitory coach for ballast cleaner |
| 25353 | | ADB975763 | Overhead Line Maintenance generator & stores coach |
| 25356 | 18356 | ADB977321 | Crewe works diesel loco test train coach |
| 25358 | | ADB975743 | Overhead Line Maintenance office & staff coach |
| 25388 | | ADB975723 | Overhead Line Maintenance generator & stores coach |
| 25396 | | TDB977174 | Train crew training coach |
| 25407 | 18407 | TDB977407 | MOD special instruction coach |
| 25412 | 18412 | TDB977584 | Special instruction coach |
| 25420 | | ADB975713 | Overhead Line Maintenance stores coach |
| 25422 | 18422 | TDB977499 | Special instruction coach |
| 25429 | | DB975817 | Underframes used for CCE staff & dormitory portakabin |
| 25430 | | ADB975758 | Overhead Line Maintenance stores coach |
| 25434 | | ADB975711 | Overhead Line Maintenance stores coach |
| 25437 | | ADB975762 | Overhead Line Maintenance generator & stores coach |
| 25440 | | ADB975744 | Overhead Line Maintenance office & staff coach |
| 25461 | | ADB975767 | Overhead Line Maintenance stores & roof access coach |
| 25466 | | ADB975714 | Overhead Line Maintenance stores coach |
| 25477 | | ADB975766 | Overhead Line Maintenance stores & roof access coach |
| 25479 | | ADB975738 | Overhead Line Maintenance stores & roof access coach |
| 25480 | | DB975825 | Underframes used for CCE staff & dormitory portakabin |
| 25493 | | DB975822 | Underframes used for CCE staff & dormitory portakabin |
| 25494 | | TDB977237 | MOD special instruction coach |
| 25495 | | ADB975759 | Overhead Line Maintenance stores coach |
| 25497 | | DB975830 | Underframes used for CCE staff & dormitory portakabin |
| 25498 | | ADB975947 | Overhead Line Maintenance cable flat |
| 25507 | | ADB975800 | CCE staff & dormitory coach for ballast cleaner |
| 25567 | | TDB977129 | MOD Special instruction coaches |
| 25570 | 18570 | TDB977408 | MOD spechal instruction coach |
| 25600 | | ADB975721 | Overhead Line Maintenance generator & stores coach |
| 25602 | 18602 | DB977724 | CE staff & tool coach |
| 25623 | | CDB977100 | EMU barrier coach |
| 25664 | | ADB975741 | Overhead Line Maintenance office & staff coach |
| 25666 | | ADB975444 | Crewe works test train |
| 25667 | | DB975824 | Underframes used for CCE staff & dormitory portakabin |
| 25669 | | DB975821 | Underframes used for CCE staff & dormitory portakabin |
| 25695 | | ADB975734 | Overhead Line Maintenance stores & roof access coach |
| 25696 | | ADB975804 | CCE staff & dormitory coach for ballast cleaner |
| 25699 | | DB975823 | Underframes used for CCE staff & dormitory portakabin |
| 25729 | 18729 | ADB977982 | Brake Force Runner |
| 25735 | 18735 | TDB977653 | Special instruction coach |
| 25755 | 18755 | TDB977419 | Special instruction coach |
| 25764 | | ADB975731 | Overhead Line Maintenance stores & roof access coach |
| 25807 | 18807 | TDB977420 | Special instruction coach |
| 25811 | 18811 | TDB977514 | Driver training coach |
| 25831 | 18831 | TDB977458 | Driver training coach |
| 25840 | 18840 | TDB977459 | Driver training coach |
| 25846 | 18846 | TDB977515 | Driver training coach |
| 25852 | 18852 | TDB977429 | Special instruction coach |
| 25859 | 18859 | TDB977428 | Special instruction coach |
| 25860 | 18860 | TDB977516 | Driver training coach |
| 25878 | 18878 | TDB977517 | Driver training coach |
| 25884 | 18884 | TDB977460 | Driver training coach |
| 25885 | 18885 | TDB977461 | Driver training coach |
| 25953 | | ADB975866 | EMU barrier coach |
| 25973 | 18973 | TDB977462 | Driver training coach |
| 25985 | 18985 | TDB977463 | Driver training coach |
| 26002 | 19002 | TDB977464 | Driver training coach |
| 26010 | 19010 | TDB977465 | Driver training coach |
| 26020 | 19020 | TDB977512 | Driver training coach |
| Mk2a ||||
| FK | SK | Departmental | Notes |
| 13458 | 19458 | RDB977914 | Test Train coach |
| 13462 | 19465 | 6352 | Mk4 Barrier coach |
| 13466 | 19466 | TDB977662 | MOD Special instruction coach |
| Mk2b ||||
| FK | SK | Departmental | Notes |
| 13476 | 19476 | RDB977525 | Brake force runner |
| 13478 | 19478 | 6353 | Mk4 Barrier coach |
| 13481 | 19481 | RDB977530 | Brake force runner |
| 13484 | 19484 | RDB977528 | Brake force runner |
| 13485 | 19485 | TDB977663 | MOD Special instruction coach |
| 13487 | 19487 | RDB977529 | Brake force runner |
| 13491 | 19491 | TDB977661 | MOD Special instruction coach |
| 13501 | 19501 | TDB977656 | MOD Special instruction coach |
| 13505 | 19505 | TDB977654 | MOD Special instruction coach |
| 13511 | 19511 | TDB977660 | MOD Special instruction coach |
| Mk2c ||||
| FK | SK | Departmental | Notes |
| 13518 | 19518 | TDB977659 | MOD Special instruction coach |
| 13531 | 19531 | TDB977658 | MOD Special instruction coach |
| 13557 | 19557 | TDB977655 | MOD Special instruction coach |

## Corridor Brake Standard/Second

A second corridor coach with a guard's brake compartment is designated BSK. The Mark 1 BSKs had 4 compartments, built as two variants with or without arm-rests depending on region, as with the SKs.