Smaller, less powerful engines also allowed savings in civil engineering as they permitted lighter-laid track and cheaper bridges. In turn this acted against the widespread adoption of larger, heavier engines as this would require a simultaneous large-scale civil engineering programme to improve the Midland's permanent way and associated structures. Similarly, the Midland was unusual among British railways by continuing to favour roundhouses to stable and service its locomotives instead of the more common longitudinal shed. While a shed could be relatively easy expanded and lengthened to accommodate larger locomotives, the roundhouses could not, further adding a secondary cost to adopting large engines. Another such factor was that decades of running light, short trains meant that the Midland's network featured shorter-than-average sidings and passing loops - if more powerful locomotives were to be procured and used to the full, these would have to be rebuilt to work with longer trains.