Rail Users Ireland (previously Platform 11) is a rail transport pressure group in Ireland whose agenda is centred on the idea that there is an economic case for expanding rail transport in Ireland through better utilisation of existing infrastructure with only justified expansion of existing routes.
 Through press releases, lobbying and leafleting they have promoted the DART Underground, a proposal to build a tunnel south of the Liffey to link up Dublin's Heuston Station with the existing DART and Luas lines.
 The group is a member of the European Passengers Federation a European level representative body for rail users which shares the same outlook in terms of sustainable transport provision and improving standards on public transport.
The history of rail transport in El Salvador began in 1882, with the opening of El Salvador's first line.
 All rail transport was suspended in 2002.
 However, limited services were resumed in 2007, between San Salvador, Ciudad Delgado and Apopa.
Rail transport can be found in every theme park resort property owned or licensed by Walt Disney Parks and Resorts, the theme park and vacation resort segment of the larger Walt Disney Company.
 The origins of Disney theme park rail transport can be traced back to Walt Disney himself and his personal fondness for railroads, who insisted that they be included in the first Disney park, the original Disneyland (a key component of the Disneyland Resort) in California in the United States, which opened on July 17, 1955.
 The Disney tradition of including transport by rail in its parks has since been extended to other Disney properties with the opening of Walt Disney World in Florida in the United States, Tokyo Disney Resort in Japan, Disneyland Paris in France, Hong Kong Disneyland Resort in China, and Shanghai Disney Resort in China.
Rail transport in Malaysia comprises heavy rail (including commuter rail), light rapid transit (LRT), monorail, airport rail link and a funicular railway line.
 Heavy rail is mostly used for intercity passenger and freight transport as well as some urban public transport, while LRTs are used for intra-city urban public transport and some special uses, such as transporting passengers between airport buildings.
 There are two commuter rail services linking Kuala Lumpur with the Kuala Lumpur International Airport.
 The sole monorail line in the country is also used for public transport in Kuala Lumpur, while the only funicular railway line is in Penang.
A valve shim is a disc of hardened metal of precisely calibrated height, used to adjust the clearance (US: lash) between the back side of the cam-lobe and the valve on which it operates, where the cam-lobe operates directly on the valve without an intermediate rocker arm.
 The shim sits atop a shim bucket which itself sits atop the valve-stem, and moves up and down within a machined bore.
 While hydraulically self-adjusting valves are sometimes preferred, because they require no adjustment, they do not work well in engines capable of high RPMs.
 In those, shims are most often used.
 As an example, most motorcycle engines capable of 8000RPM+ use shim-adjustable valves.
Hohensalzburg Castle (German: "Festung Hohensalzburg" , literally "High Salzburg Fortress") sits atop the Festungsberg, a small hill in the Austrian city of Salzburg.
 Erected at the behest of the Prince-Archbishops of Salzburg with a length of 250 m and a width of 150 m , it is one of the largest medieval castles in Europe.
 Hohensalzburg Castle is situated at an altitude of 506 m.
Transport in Greater Nagoya (Chūkyō) is similar to that of the Tokyo and Osaka, but is more automobile oriented, as the urban density is less than Japan's two primary metropolises, and major automobile manufacturers like Toyota are based here.
 Still, compared to most cities of its size worldwide it has a considerable rail transport network with 3 million passenger trips daily, with a similar density and extent of passenger rail to London or New York City, (as of May 2014, the article Nagoya rail list lists 59 lines, 16 operators, 1,547.8 km of operational track and 654 stations [although stations recounted for each operator], note this data does not include any high speed rail) complemented with highways and surface streets for private motor transport.
 It includes public and private rail and highway networks; airports for international, domestic, and general aviation; buses; motorcycle delivery services, walking, bicycling, and commercial shipping.
 The nexus of the public transport system is Nagoya Station.
 Every region of Greater Nagoya, also known as the Chūkyō Metropolitan Area (中京圏 ) , has rail or road transport services, and the area as a whole is served by sea and air links.
Rail transport in Central America consists of several isolated railroad lines with freight or passenger service.
 The most famous one is the Panama Canal Railway, the oldest transcontinental railroad in the world, connecting Panama City with Colón since 1855.
 Other railroads in Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica and Panama were built by private and public investors mainly to facilitate the transport of local agricultural produce (bananas, coconuts, coffee) to export markets and harbors.
 Their market share and profitability went into decline in the second half of the twentieth century and most lines have been decommissioned by the end of the 1990s.
 As of 2010, railroads operate locally in El Salvador, Honduras, Costa Rica and Panama only; all rail transport has been suspended in Belize, Guatemala and Nicaragua.
 None of the operating railways crosses national borders.
Rail transport in Puerto Rico currently consists of a 10.7 mi passenger metro system in the island's metropolitan area of San Juan.
 Its history can be traced back to the mid-19th century with the construction of a limited passenger line in Mayagüez.
 Between the late 19th and early 20th centuries, Puerto Rico's rail transport system expanded significantly, becoming one of the largest rail systems in the Caribbean at the time thanks to an economic boom in agriculture industries, especially the sugar cane industry.
 The rail system was expanded to include passenger travel with a direct line from the island's northern capital of San Juan to the western and southern cities and towns, greatly improving travel and communication within the island.
 However, the entire system was soon overshadowed by the arrival of the automobile, and by the 1950s was completely abandoned.
 Small remnants of this system still exist in some parts of Puerto Rico, some conserved for tourism purposes.
The history of rail transport in Austria began with the Reisszug, a private funicular serving the Fortress of Salzburg.
 Built at the end of the 15th century and first documented in 1515, it is the oldest known funicular in the world, and possibly the oldest existing railway line.

Question: What is the altitude of the castle that sits atop of a hill in the city where the history of rail transport in Austria began?
Answer: 506 m.