Timeline consistency check
In 1530/05,  StageWagonCool is introduced, is unbuildable because none of its constraints are available until 1750/01, when RoadHorsesDouble becomes available.
In 1530/05,  StageWagonMail is introduced, is unbuildable because none of its constraints are available until 1750/01, when RoadHorsesDouble becomes available.
In 1530/05,  StageWagonPiece is introduced, is unbuildable because none of its constraints are available until 1750/01, when RoadHorsesDouble becomes available.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering WagonLong unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering CartMail unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesSingle, RoadHorsesDouble) retire... rendering WagonCool unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering CartBulk unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesSingle, RoadHorsesDouble) retire... rendering WagonPiece unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesSingle, RoadHorsesDouble) retire... rendering CartCool unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering WagonBulk unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering CartLong unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering CartPiece unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(RoadHorsesDouble, RoadHorsesSingle) retire... rendering HackneyCarriage unbuildable until 1918/03 when it retires.
** SteamBargeCool is not defined; it is required as a constraint of HorseBargeLivestock.
** SteamBargeBulk is not defined; it is required as a constraint of HorseBargeLivestock.
** SteamBargeLivestock is not defined; it is required as a constraint of HorseBargeLivestock.
** SteamBargeOil is not defined; it is required as a constraint of HorseBargeLivestock.
** SteamBargeLong is not defined; it is required as a constraint of HorseBargeLivestock.
** SteamBargePiece is not defined; it is required as a constraint of HorseBargeLivestock.
In 1918/01, vehicles(BoatHorsesSingle, BoatHorsesDouble) retire... rendering HorseBargeLivestock unbuildable until 1930/01, when DieselBargeBulk becomes available, making HorseBargeLivestock buildable again.
In 1918/01, vehicles(BoatHorsesSingle, BoatHorsesDouble) retire... rendering HorseBargeLong unbuildable until 1930/01, when DieselBargeBulk becomes available, making HorseBargeLong buildable again.
In 1918/01, vehicles(BoatHorsesSingle, BoatHorsesDouble) retire... rendering HorseBargeBulk unbuildable until 1930/01, when DieselBargeBulk becomes available, making HorseBargeBulk buildable again.
In 1918/01, vehicles(BoatHorsesDouble, BoatHorsesSingle) retire... rendering HorseBargePiece unbuildable until 1930/01, when DieselBargeLivestock becomes available, making HorseBargePiece buildable again.
In 1918/01, vehicles(BoatHorsesSingle, BoatHorsesDouble) retire... rendering HorseBargeCool unbuildable until 1930/01, when DieselBargeBulk becomes available, making HorseBargeCool buildable again.
In 1918/01, vehicles(BoatHorsesSingle) retire... rendering TubBoatLong unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(BoatHorsesSingle) retire... rendering TubBoatBulk unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(BoatHorsesSingle) retire... rendering TubBoatPiece unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(BoatHorsesSingle) retire... rendering TubBoatCool unbuildable until 1918/03 when it retires.
In 1918/01, vehicles(BoatHorsesDouble) retire... rendering FlyboatMail unbuildable until 1940/01 when it retires.
In 1918/01, vehicles(BoatHorsesDouble) retire... rendering FlyboatCool unbuildable until 1940/01 when it retires.
In 1918/01, vehicles(BoatHorsesDouble) retire... rendering FlyboatPax unbuildable until 1940/01 when it retires.
In 1918/01, vehicles(BoatHorsesDouble) retire... rendering FlyboatPiece unbuildable until 1940/01 when it retires.
 ** LBSCR-4wheel-open has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-4wheel-open.
In 1860/01, vehicles(IronPaddleSteamer, PSPremier) retire... rendering IronPaddleSteamerMail unbuildable until 1877/01 when it retires.
In 1845/04,  LNWR-crewe-type is introduced, is unbuildable because none of its constraints are available until 1851/01, when LNWR-Bloomer-Tender(Red) becomes available.
 ** LBSCR-4wheel-open-sided has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-4wheel-open-sided.
In 1849/10,  LNWR-Sharp-goods is introduced, is unbuildable because none of its constraints are available until 1851/01, when LNWR-Bloomer-Tender(Red) becomes available.
** WoodenHullUnpoweredNarrowboatMail is not defined; it is required as a constraint of SteamNarrowboatTug.
** SteelHullUnpoweredNarrowboatMail is not defined; it is required as a constraint of SteamNarrowboatTug.
** CompositeHullUnpoweredNarrowboatMail is not defined; it is required as a constraint of SteamNarrowboatTug.
 ** LBSCR-4wheel-parliamentary-third has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-4wheel-parliamentary-third.
 ** LBSCR-4wheel-parliamentary-second has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-4wheel-parliamentary-second.
In 1852/05,  LBSCR-standard-goods-tender is introduced, is unbuildable because none of its constraints are available until 1855/02, when LBSCR-long-boiler-mixed becomes available.
In 1852/05,  LBSCR-craven-tender is introduced, is unbuildable because none of its constraints are available until 1854/11, when LBSCR-croydon becomes available.
 ** 4-wheel-1850s-mail(MR) has next of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have prev of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has next of LMR-4Wheel-Mail-Guard-rear, but LMR-4Wheel-Mail-Guard-rear does not have prev of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has next of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have prev of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has next of LMR-4Wheel-First-Guard-rear, but LMR-4Wheel-First-Guard-rear does not have prev of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s-mail(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1850s-mail(MR).
 ** 4-wheel-1850s(MR) has next of LMR-4Wheel-Mail-Guard-rear, but LMR-4Wheel-Mail-Guard-rear does not have prev of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has next of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have prev of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has next of LMR-4Wheel-First-Guard-rear, but LMR-4Wheel-First-Guard-rear does not have prev of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has next of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have prev of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1850s(MR).
 ** 4-wheel-1850s(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1850s(MR).
 ** 4-wheel-1850s-tpo(MR) has next of LMR-4Wheel-Mail-Guard-rear, but LMR-4Wheel-Mail-Guard-rear does not have prev of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has next of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have prev of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has next of LMR-4Wheel-First-Guard-rear, but LMR-4Wheel-First-Guard-rear does not have prev of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has next of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have prev of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1850s-tpo(MR).
 ** 4-wheel-1850s-tpo(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1850s-tpo(MR).
 ** LBSCR-20ft-mail has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-20ft-mail.
 ** LBSCR-20ft-third has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-20ft-third.
 ** LBSCR-20ft-brake-rear has prev of LBSCR-4Wheel-First, but LBSCR-4Wheel-First does not have next of LBSCR-20ft-brake-rear.
In 1871/07, vehicles(LBSCR-standard-goods-tender) retire... rendering LBSCR-small-goods unbuildable until 1874/11 when it retires.
 ** 4-wheel-1860s-mail(MR) has next of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have prev of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has next of LMR-4Wheel-Mail-Guard-rear, but LMR-4Wheel-Mail-Guard-rear does not have prev of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has next of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have prev of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has next of LMR-4Wheel-First-Guard-rear, but LMR-4Wheel-First-Guard-rear does not have prev of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-mail(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1860s-mail(MR).
 ** 4-wheel-1860s-tpo(MR) has next of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have prev of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has next of LMR-4Wheel-First-Guard-rear, but LMR-4Wheel-First-Guard-rear does not have prev of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has next of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have prev of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has next of LMR-4Wheel-Mail-Guard-rear, but LMR-4Wheel-Mail-Guard-rear does not have prev of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s-tpo(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1860s-tpo(MR).
 ** 4-wheel-1860s(MR) has next of LMR-4Wheel-Mail-Guard-rear, but LMR-4Wheel-Mail-Guard-rear does not have prev of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has next of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have prev of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has next of LMR-4Wheel-First-Guard-rear, but LMR-4Wheel-First-Guard-rear does not have prev of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has next of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have prev of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1860s(MR).
 ** 4-wheel-1860s(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1860s(MR).
 ** 4-wheel-1860s-brake-rear(MR) has prev of LMR-4Wheel-Mail-Guard-front, but LMR-4Wheel-Mail-Guard-front does not have next of 4-wheel-1860s-brake-rear(MR).
 ** 4-wheel-1860s-brake-rear(MR) has prev of LMR-4Wheel-Mail, but LMR-4Wheel-Mail does not have next of 4-wheel-1860s-brake-rear(MR).
 ** 4-wheel-1860s-brake-rear(MR) has prev of LMR-4Wheel-First-Guard-front, but LMR-4Wheel-First-Guard-front does not have next of 4-wheel-1860s-brake-rear(MR).
 ** 4-wheel-1860s-brake-rear(MR) has prev of LMR-4Wheel-Parliamentary, but LMR-4Wheel-Parliamentary does not have next of 4-wheel-1860s-brake-rear(MR).
** ClydeSteamerMail is not defined; it is required as a constraint of ClydeSteamer.
In 1860/01,  ClydeSteamer is introduced, is unbuildable because none of its constraints are available until 1886/06 when it retires.