|Service type||Regional rail|
|End||New Center, Detroit|
|Distance travelled||39.72 mi (63.92 km)|
|Average journey time||45 minutes|
|Service frequency||8 round-trips per day|
|Line(s) used||Michigan Line|
|Track gauge||1,435 mm (4 ft 8 1⁄2 in) standard gauge|
Ann Arbor–Detroit Regional Rail (also known as MiTrain and formerly known as SEMCOG Commuter Rail [note 1]) is a planned regional rail link along the Michigan Line between the cities of Ann Arbor and Detroit, Michigan, a total length of 39.72 miles (63.92 km).  The project would connect with a proposed Detroit bus rapid transit service and the QLine streetcar. 
Detroit previously had commuter rail service. Until 1983, SEMTA operated Grand Trunk Western Railroad's former service between downtown Detroit, and Pontiac, Michigan. Amtrak continued Penn Central Detroit–Ann Arbor commuter service as the Michigan Executive until 1984.
In May 2009 SEMCOG commissioned a $200,000 study to determine whether commuter trains could operate along the same corridor as Amtrak intercity passenger trains and freight trains.  As of November 2012 [update] limited service for special events in Detroit was scheduled to begin in early 2013, while regular commuter service was scheduled for 2014, after further track upgrades are completed.  As of October 2013 [update] no operating funds had been identified and service was at least two years out. 
From November 12 to 14, 2012, testing of the railcar fleet by an Amtrak GE Dash 8-32BWH locomotive took place between Pontiac and Jackson; while service will only initially operate between Ann Arbor and Detroit, testing the fleet on additional trackage eases the process required for future expansion to Jackson and Pontiac.  The locomotives have not yet been tested.
The plan was folded into the RTA's master plan in May 2016.  The service is estimated to cost $11-$19 million to operate annually, and $130 million in capital costs to start. The service is scheduled to begin in 2022. 
The service is proposed to operate eight round-trips during each day: three during morning and afternoon rush-hours, one during the midday, and one in the evening.  An end-to-end ride is estimated to take 45 minutes, and there would be stops at Ann Arbor, Ypsilanti, Wayne, Dearborn and the New Center neighborhood in Detroit. Of these stops, four are existing or proposed Amtrak stations, and one (Wayne) would be a new station used exclusively for the regional rail service. 
SEMCOG Commuter Rail's rolling stock are all ex- Metra Budd bi-level gallery-type cars as the passenger cars and the locomotives are ex- GO Transit EMD F59PH units currently owned by RB Railway Leasing.  SEMCOG has painted its rolling stock. Like on Metra cab cars, SEMCOG's cab cars have red and white warning stripes at the front. They have plates that say "MiTrain" on the sides.
- SEMCOG stands for Southeast Michigan Council of Governments, and is a collection of town, township, county, and city governments
- "Master Plan". Regional Transit Authority of Southeast Michigan. Retrieved August 4, 2016.
- Stolarz, Christina (May 21, 2009). "SEMCOG to spend $200K on Ann Arbor–Detroit rail study". The Detroit News. Retrieved May 21, 2009.[ dead link]
- "Michigan tests cars for future commuter service". Trains Magazine. November 13, 2012. Retrieved November 19, 2012.(subscription required)
- Regional Transit: Where Does Ann Arbor Fit?
- Fleming, Leonard N. (May 20, 2016). "RTA wants Detroit-Ann Arbor commuter rail service". The Detroit News. Retrieved August 4, 2016.
- "Michigan Avenue Corridor Study Locally Preferred Alternative Report DRAFT May 2016" (PDF). Regional Transit Authority of Southeast Michigan. Retrieved August 4, 2016.
- Ann Arbor-Downtown Detroit Transit Study: Detailed Screening of Alternatives[ permanent dead link]