How and why did transportation developments spark economic growth during the period 1860 to 1900 in the US?

railroads did this fantastic thing thing called transporting people!!! tied the Union together physically as well as economically. The puffing locomotives opened up fresh markets for manufactured goods and sped raw materials to factories. The iron horse (that's the railroad for you idiots) also stimulated mining and agriculture, especially in the West, it took farmers out to their land, carried the fruits of their toil to market, and brought them their manufactured necessities. The iron monsters could carry food to enormous concentrations of people and at the same time ensure them a livelihood by providing both raw materials and markets. Railroad companies even stimulated the mighty stream of migration. Seeking settlers to whom their land grants might be sold at a profit, they advertised seductively in Europe and sometimes offered to transport the newcomers free to their farms.

Then there was this magical thing called steam boats, they brought people across seas easier and faster, ooh (sarcasm).

The seas experienced a major transportation development, iron ships. Iron ships made traveling to other countries faster and easier, this made it safer for immigrants to travel to the U.S The large amount of immigrants provided cheap labor for companies and industries, these industries would flourish later. The immigrants helped to develop the economy by contributing greatly to the building of railroads, they were brought over by newly developed transportation systems and settled largely in cities where they helped to develop factories and industries. The immigrants were a large part of sparking economic growth from 1860 to 1890, if not for them; the U.S may not have flourished so quickly. Hoped this helped all you dumbasses out there, my apologies, APUSH is so sophomore year for me.