Search results for "Transportation technology"
showing 3 items of 3 documents
Changes in Transport and Non Transport Costs: Local vs. Global Impacts in a Spatial Network
2007
We develop a multi-country Dixit-Stiglitz trade model and analyze how industry location and welfare respond to changes in: (i) transport frictions (e.g., infrastructure, transportation technology); and (ii) non-transport frictions (e.g., tariffs, standards and regulations). We show that changes in non-transport frictions, which are usually origin-destination specific, do not allow for any clear prediction as to changes in industry location and welfare; whereas changes in transport frictions, which are usually not origin-destination specific, may allow for such predictions. In particular, we show that reductions in transport frictions occurring at links around which the spatial network is lo…
Identification of Bending Modes of Vibration in Rails by a Laser Doppler Vibrometer on a Moving Platform
2020
This paper introduces a method to identify the bending modes of vibration of railway tracks by using a laser Doppler vibrometer (LDV) mounted on a moving platform. Two sets of experiments were conducted at Transportation Technology Center Inc. (TTCI) in Pueblo Colorado, in order to validate the proposed method. First, the bending vibration modes were identified using the signals collected from a rail span (rail section between two consecutive sleepers) by accelerometers under moving car excitation. Then, vibration measurements from rail spans were obtained by using an LDV mounted on the moving railcar. All tests were carried out at four different rail car speeds: 8 km/h (5 mph), 16 km/h (10…
On the Location and 'Lock-In' of Cities: Geography vs. Transportation Technology
2004
We investigate where cities are located in a spatial economy and why they tend to get 'locked-in' at particular sites. Building on Fujita and Krugman (1995) we show that geography and/or transportation technology must exhibit some 'non-smoothness' for cities to possibly become 'locked-in' in location space. Our results establish that no asymmetric monocentric equilibrium can be generically sustained when space is homogenous and transportation technologies are 'smooth', whereas it can in the presence of transportation hubs and/or concave transport cost functions. This suggests that cities are drawn to transportation hubs during the early stages of economic development, whereas they can be su…