Dominant transportation system in Porto RicoEdit
Streetcars are vehicle that run on pre-laid track on street. At first, streetcars are horse-drawn which then it evolves into stream-powered or electric-powered with the invention of steam engine and combustion engine. It is a public transit before the invention of automobile and trains. At that time, streetcars are famous of its low rolling resistance of steel wheels on steel rails, plus the simple guidance mechanism offered by flanges. Hence, people use it to moves around city.
Transport before streetcarEdit
Before the emerge of streetcar, walking is the main mode for people to travel around city. Other than walking, there is also carriages and wagons which is horse-drawn as a choice. They have similar property as streetcar which moves people around but they are not favoured as they are not scheduled and dependent on pavement condition.
Emergence of streetcarEdit
The idea of streetcar has been around at beginning of 1800. However, the first commercialize streetcar is introduced by an American, John Stephenson in 1832. The technology of streetcar is similar is wagon but it has a fixed truck underneath which need knowledge of ironworks at that time. The initial design of streetcar is single carriage with capacity of 6-12 people and it is driven by multiple horses. At the peak of streetcar era, it becomes electric-powered and has larger capacity which largely depends on the number of carriages on it.
The initial market for streetcar is enable owner of streetcar to bring their customer to their shop. After some time, streetcar owners realize the potential of the service and start to expand the route to serve more places. Other than expanding their services, the builders and engineers of streetcar put in effort on improving the efficiency of streetcar. For example, John Stephenson reduces the weight of carriages by twofold of initial design and increase the number of horses from two to four.
Growth of streetcarEdit
Streetcar at that time is the best option for people to move around city. The growth of streetcar is slow at the beginning at the mode is not worth the value of cost. As the capital of streetcar reduced due to improvement of the mode from engineers and builders, it is become a popular choice for people. In parallel with the improvement of technology, there is also investors who are willing to risk their capital to build to a streetcar route of their own. The influx of private sector then causes a problem to overall traffic since they do not have a centralize management. Other than management issue, there is also maintenance issue which require a constant input of manpower to fix the road pavement. Hence, local authorities forced streetcar owners to maintain the road pavement regular and allow them to have a flat fee in their ticket sales as the payment for maintenance of road pavement. However, this policy led to every streetcar system have a fixed price for its ticket. It causes problem because people are forced to switch streetcar to go to a place when there is not centralize system. This issue is finally solved after local authorities take over the asset and maintain them with tax. This move at the time raise some opposition as this action is close to socialism proposed by Karl Marx.
An Quantitative analysis is done on the growth of streetcar system in Porto Rico. The parameter focus in this analysis is the track length of the streetcar in recorded in McGraw electric railway manual - the red book of American street railway investment. The earliest record of streetcar track is on 1902. However, streetcar is already established in Porto Rico in 1880s during colonization era of Spain. Porto Rico was surrendered to America after Spanish-American War in 1898. The streetcar system before the surrender is managed by Spanish investor who never submit their information to McGraw electric railway manual. Hence, the analysis done is only on the streetcar system submit their record in McGraw electric railway manual.
World War 1Edit
Railway in Porto Rico is heavily affected by World War 1 in 1914. Tracks is heavily damaged and reconstruction and recovery is needed to do to revived the whole streetcar system. However, some of them is not economical viable to be reconstruct which causes a significant drop of track length after 1914.
A regression study is done onto the track length. A three parameter logistic function is used
S(t) = Smax/[1+exp(-b(t-ti)]
- S(t) is the status measure, (e.g. Passenger-km traveled)
- t is time (usually in years),
- ti is the inflection time (year in which 1/2 Smax is achieved),
- Smax is saturation status level, (Choose the maximum length of the streetcar system that you have recorded in the data).
- b is a coefficient to be estimated.
The result is split into two, result includes data after 1914 and exclude data after 1914.
The analysis including data after 1914 is a invalid result since it has a low R score and an intercept year 1919 which do not make any sense. It is reasonable to have such result because after 1914, there is a drastic drop of data. The regression study assume the number always increase as the year increase. Hence it is reasonable for R score to be this low.
However, the analysis excluding data after 1914 is valid. The R score is 0.8 which is not high but it showed a high correlation of data. The t statistic of data is 6.77 which is not acceptable. However, a sharp s-curve is able to be observe from the graph. The birth state of the s-curve is at 1902 to 1906 while it has a sharp grow in 1907, After 1908, the growth of track length is stabled and we can conclude the growth is mature.