diff --git a/README.md b/README.md
index d018560..0a5a109 100644
--- a/README.md
+++ b/README.md
@@ -72,12 +72,12 @@ mta.status('subway').then(function (result) {
 The API route this method hits is updated by the MTA every 60 seconds.
 
 ### Get real-time subway schedule data
-Only available for the following routes: 1, 2, 3, 4, 5, 6, S, L, and Staten Island Railway (http://datamine.mta.info/list-of-feeds).
+Only available for the routes found in this [list](http://datamine.mta.info/list-of-feeds).
 
-Given a single subway stop id (or an array of stop ids), it gives schedule data for both northbound and southbound trains.
+Given a single subway stop id (or an array of stop ids) and an optional feedId, it gives schedule data for both northbound and southbound trains.
 
 ```Javascript
-mta.schedule(635).then(function (result) {
+mta.schedule(635, 1).then(function (result) {
   console.log(result);
 });
 ```
@@ -88,10 +88,8 @@ The API route this method hits is updated by the MTA every 30 seconds.
 
 See [test cases](https://github.com/aamaliaa/mta/blob/master/test/mta.js) for more examples.
 
-Replace `'your-api-key'` in `test/config.js` with your own MTA API key then run:
-
 ```
-npm test
+MTA_API_KEY='your-api-key-here' npm test
 ```
 
 ## To do
diff --git a/lib/mta.js b/lib/mta.js
index d2c8261..aad5cdc 100644
--- a/lib/mta.js
+++ b/lib/mta.js
@@ -21,7 +21,7 @@ var Mta = module.exports = function (options) {
   this.options = options || {};
 
   _.extend({
-    feed_id: 0
+    feed_id: 1,
   }, this.options);
 
   if (this.options.key === 'your-api-key') {
@@ -84,15 +84,22 @@ Mta.prototype.status = function (service) {
 /**
  * Gets MTA schedule status
  * @param  {String|Array} stopId
+ * @param  {String}       feedId    optional
  * @return {Object}       schedule
  */
-Mta.prototype.schedule = function (stopId) {
+Mta.prototype.schedule = function (stopId, feedId) {
 
   var schedule = {};
   var results = false;
   var stopIds;
-  var feedUrl = this.urls.gtfs + qs.stringify(_.pick(this.options, [ 'feed_id', 'key' ]));
-  var msg, direction, obj;
+  var direction, obj;
+  var options = _.pick(this.options, [ 'feed_id', 'key' ]);
+
+  if (feedId) {
+    options.feed_id = feedId;
+  }
+
+  var feedUrl = this.urls.gtfs + qs.stringify(options);
 
   if (!this.options.key) {
     throw new Error('schedule method requires MTA API key');
@@ -105,10 +112,10 @@ Mta.prototype.schedule = function (stopId) {
 
   if (_.isArray(stopId)) {
     stopIds = stopId;
-  } else if (_.isNumber(stopId)) {
+  } else if (_.isNumber(stopId) || _.isString(stopId)) {
     stopIds = [ stopId ];
   } else {
-    throw new Error('invalid stop id(s)')
+    throw new Error('invalid stop id(s)');
   }
 
   _.each(stopIds, function (stop) {
diff --git a/test/config.js b/test/config.js
deleted file mode 100644
index 5ee63db..0000000
--- a/test/config.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = {
-  key: 'your-api-key'
-};
diff --git a/test/mta.js b/test/mta.js
index d0ef636..6f11b50 100644
--- a/test/mta.js
+++ b/test/mta.js
@@ -1,7 +1,10 @@
 var should = require('should');
-var config = require('./config');
 var Mta = require('../lib/mta');
 
+var config = {
+  key: process.env.MTA_API_KEY,
+};
+
 describe('MTA', function () {
   var mta,
     serviceType,
@@ -68,12 +71,12 @@ describe('MTA', function () {
     });
   });
 
-  it('api key is set in test/config.js', function (done) {
-    config.key.should.not.equal('your-api-key');
+  it('MTA_API_KEY should be set', function (done) {
+    config.key.should.not.equal('');
     done();
   });
 
-  it('should get schedule info for 1 MTA subway station', function () {
+  it('should get schedule info for 1 MTA subway station (number input)', function () {
     return mta.schedule(stopId)
     .then(function (result) {
       result.should.have.property('schedule');
@@ -82,6 +85,24 @@ describe('MTA', function () {
     });
   });
 
+  it('should get schedule info for 1 MTA subway station (string input)', function () {
+    return mta.schedule('128')
+    .then(function (result) {
+      result.should.have.property('schedule');
+      result.should.have.property('updatedOn');
+      result.schedule['128'].should.exist;
+    });
+  });
+
+  it('should get schedule info for a station with a different feed_id', function () {
+    return mta.schedule('A15', 26)
+    .then(function (result) {
+      result.should.have.property('schedule');
+      result.should.have.property('updatedOn');
+      result.schedule['A15'].should.exist;
+    });
+  });
+
   it('should get schedule info for multiple MTA subway stations', function () {
     return mta.schedule(stopIds)
     .then(function (result) {