The most common wagons used for hauling freight back East were the Conestogas, developed in Pennsylvania by descendants of German colonists. Conestoga wagons were large, heavy, and had beds shaped somewhat like boats, with angled ends and a floor that sloped to the middle so barrels wouldn't roll out when the wagon was climbing or descending a hill. Like the covered wagons of the western pioneers, it had a watertight canvas bonnet to shelter the cargo. Conestogas were pulled by teams of six or eight horses and could haul up to five tons.
Traders on the Santa Fe Trail adopted the Conestoga design for its durability and size, but they found that bullwhackers or muleskinners were preferable to teamsters -- the immense distances and scarcity of good water along the Santa Fe Trail precluded the use of horses as draft animals. Teams of up to two dozen oxen or mules were used to haul the heaviest loads. Sometimes a second wagon, or "backaction," was hitched behind the lead wagon.
Overlanders on the Oregon Trail, in contrast, quickly learned that Conestoga wagons were too big for their needs: the huge, heavy wagons killed even the sturdiest oxen before the journey was two-thirds complete. Their answer to the problem was dubbed the "Prairie Schooner," a half-sized version of the Conestoga that typically measured 4' wide and 10' to 12' in length. With its tongue and neck yoke attached, its length doubled to about 23 feet. With the bonnet, a Prairie Schooner stood about 10' tall, and its wheelbase was over 5' wide. It weighed around 1300 pounds empty and could be easily dismantled for repairs en route. Teams of 4 to 6 oxen or 6 to 10 mules were sufficient to get the sturdy little wagons to Oregon. Manufactured by the Studebaker brothers or any of a dozen other wainwrights specializing in building wagons for the overland emigrants, a Prairie Schooner in good repair offered shelter almost as good as a house.
The wagon box, or bed, was made of hardwoods to resist shrinking in the dry air of the plains and deserts the emigrants had to cross. It was 2' to 3' deep, and with a bit of tar it could easily be rendered watertight and floated across slow-moving rivers. The side boards were beveled outwards to keep rain from coming in under the edges of the bonnet and to help keep out river water. The box sat upon two sets of wheels of different sizes: the rear wheels were typically about 50" in diameter, while the front wheels were about 44" in diameter. The smaller front wheels allowed for a little extra play, letting the wagon take slightly sharper turns than it would otherwise have been able to negotiate without necessitating a great deal of extra carpentry work to keep the bed level. All four wheels had iron "tires" to protect the wooden rims, and they were likewise constructed of hardwoods to resist shrinkage. Nonetheless, many emigrants took to soaking their wagon wheels in rivers and springs overnight, as it was not unheard of for the dry air to shrink the wood so much that the iron tires would roll right off the wheels during the day.
Hardwood bows held up the heavy, brown bonnets. The bows were soaked until the wood became pliable, bent into U-shapes, and allowed to dry. They would hold their shape if this was done properly, which was important to the emigrants: if the wagon bows were under too much tension, they could spring loose and tear the bonnet while the wagon was jostled and jounced over rough terrain. The bonnets themselves were usually homespun cotton doubled over to make them watertight. They were rarely painted (except for the occasional slogan such as "Pike's Peak or Bust" in later years) as this stiffened the fabric and caused it to split. The bonnet was always well-secured against the wind, and its edges overlapped in back to keep out rain and dust. On some wagons, it also angled outward at the front and back, as shown in the illustration above, to lend some additional protection to the wagon's interior.
While wagons were minor marvels of Nineteenth Century engineering, they inevitably broke down or wore out from the difficulty and length of the journey. Equipment for making repairs en route was carried in a jockey box attached to one end or side of the wagon. It carried extra iron bolts, linch pins, skeins, nails, hoop iron, a variety of tools, and a jack. Also commonly found slung on the sides of emigrant wagons were water barrels, a butter churn, a shovel and axe, a tar bucket, a feed trough for the livestock, and a chicken coop. A fully outfitted wagon on the Oregon Trail must have been quite a sight, particularly with a coop full of clucking chickens raising a ruckus every time the wagon hit a rock.
There was only one set of springs on a Prairie Schooner, and they were underneath the rarely-used driver's seat. Without sprung axles, riding inside a wagon was uncomfortable at the best of times. Some stretches of the Trail were so rough that an overlander could fill his butter churn with fresh milk in the morning, and the wagon would bounce around enough to churn a small lump of butter for the evening meal. The simple leaf springs under the driver's seat made that perch tenable, but not particularly comfortable. The illustration above does not show the driver's seat, and its placement of the brake lever is questionable. The brake lever was usually located so it could be pressed by the driver's foot or thrown by someone walking alongside the wagon, and it was ratcheted so the brake block would remain set against the wheel even after pressure was taken off the lever.
While Prairie Schooners were specifically built for overland travel, many emigrants instead braved the Oregon Trail in simple farm wagons retrofitted with bonnets. Farm wagons were typically slightly smaller than Prairie Schooners and not as well sheltered, as their bonnets usually were not cantilevered out at the front and back, but they were quite similar in most other respects.