Birmingham

Alabama's largest city, Birmingham currently doesn't have any rapid transit system (though a downtown streetcar has been proposed). The metro area population of over 1,100,000, with large population spread throughout the connected regional towns. The dreamed-of system has five lines which converge on the downtown station, which also provides connection to Amtrak with service to New Orleans, Atlanta, Washington, and New York.

Lines

• Yellow: 39.8 miles, 17 stations
• Red: 24.5 miles, 15 stations
• Cyan: 29.2 miles, 14 stations
• Violet: 18.5 miles, 11 stations
• Orange: 42.3 miles, 19 stations

Tampa

The Tampa Bay Area, including Tampa, Clearwater, and St Petersburg, is home to over 4 million people, and represents another colossal urban complex without any existing rapid transit (barring the heritage TECO streetcar line). Its six lines provide connections to two Amtrak stations, as well as the Orlando regional rail system (coming soon).

Lines

• Light Blue: 77.8 miles, 29 stations
• Orange: 56.2 miles, 16 stations
• Green: 47.9 miles, 12 stations
• Navy: 14.8 miles, 10 stations
• Lavender: 59.5 miles, 14 stations
• Yellow: 59.8 miles, 19 stations

Houston

Houston is the largest city I've tackled with over 6 million people in the metropolitan region, which really means it's the largest in the country without a major metro system. This is changing however, with its first light rail line in 2013, and two smaller routes opening earlier this year. The extensive existing train tracks also made for an impressive dreamed-of system, with five lines and over 100 stations.

Houston's Amtrak station is served by the yellow and cyan lines, and all lines have transfers to the light rail system at at least either University Downtown or Eado Transfer, as indicated by the MetroRail icons [I added an additional light rail station at Fulton transfer]. This time, I did build in shuttle buses to connect Houston's two airports to nearby rail lines.

Lines

• Blue: 57.7 miles, 22 stations
• Cyan: 66.3 miles, 26 stations
• Yellow: 46 miles, 18 stations
• Lavender: 82.2 miles, 28 stations
• Green: 73.3 miles, 23 stations

Indianapolis

This scheme gives a transit system to Indiana's capital and largest city. Like Norfolk, one of the lines borders the non-terminal side of the airport and so is close, but lacks a connection. The city center station also serves Amtrak's long-distance lines, with daily service to Chicago and three trains a week to Washington and New York.

Lines

• Blue: 39.9 miles, 21 stations
• Cyan: 33.3 miles, 23 stations
• Red: 35.5 miles, 23 stations
• Pink: 26 miles, 14 stations
• Black, 44 miles, 31 stations

Raleigh

The Raleigh regional rail system connects Raleigh with Cary and Durham, as well as many of the office parks in this "Research Triangle" region. There are also five universities served by the system, and connection to long-distance rail at three Amtrak stations.

Lines

• Orange, 26.7 miles, 13 stations
• Blue, 55.4 miles, 31 stations
• Black, 25.5 miles (including Durham loop, runs clockwise), 17 stations
• Red, 35.9 miles, 26 stations
• Yellow, 17.7 miles, 11 stations

Norfolk

The Norfolk system serves many of the connected cities in Virginia's largest metropolitan region. Shame there isn't a connection across the James River to Newport News. The new rail system provides an interchange with the existing Tide Light Rail system at Harbor Park, where there is also a connection to Amtrak's recently added Norfolk service. While the Orange Line does border the edge Norfolk's airport, it's opposite the terminal and wouldn't provide convenient access.

Lines

• Tide Light Rail (Blue, diamonds on the interactive map): 7.3 miles, 11 stations
• Yellow: 14.5 miles, 10 stations
• Orange: 29.2 miles, 13 stations
• Green: 17.5 miles, 7 stations
• Cyan (Crosstown): 16.2 miles, 12 stations

Wayfinding available

Madison

Madison was one of last systems to plan, but the first to create a schematic map for. Its natural 45-degree angle paths along and above the isthmus lent themselves nicely to the diagram format. It's also one of the smaller networks, serving a metro area of 627,00 people. Madison has a great convergence of lines downtown just a quarter mile from the capitol building. The Green Line has a stop within walking distance of the airport terminal, though Madison lacks an Amtrak station to make long-distance rail connections (thanks, Scott Walker!).

Lines

• Blue: 18.5 miles, 12 stations
• Green: 17.7 miles, 10 stations
• Purple: 15.0 miles, 9 stations
• Red, 19.5 miles, 15 stations

Introduction

Welcome to the blog. I've looked over maps of many of the largest cities in the U.S. which have little or no rapid transit, and carved out some possibilities for them. Here are the rules/notes:

1. Existing train tracks. All the new routes only use currently developed rail lines. Many of these may be active (or occasional) freight routes, which adds expense by the added complications to comply with the FRA shared track requirements. However, this is more than made up by using existing right-of-ways and minimizing tunnels, elevated lines, and land acquisition. 
2. Mile spacing. Stations are at least one mile from their neighbors on the same line, except in the city center, where they can be as close as half a mile.
3. Through-running trains. Whenever possible, the lines pass through the city center rather than terminating in the core. This allows for reverse- and through-commuting and minimizing storage yard requirements in locations where there is the least room.
4. Station colors. White with black circle stations service more than one line. Extra large stations are either city centers or major transfer points. Solid colored circles are served by a single line during all operating hours. Small white circles with colored backgrounds are for outlying communities and are served only during peak hours. Tick marks are existing (in real life) light rail stations.
5. Line colors. Mostly anything goes, with a fair amount of whim and chance. But there are 2 rules: black lines are used where the right-of-way is intact (or nearly so), but the tracks are missing or impassible, and so would require a bit more to get up to working order; grey lines are used for an existing (in real life) commuter rail system.