diff --git a/packages/router/src/apply_redirects.ts b/packages/router/src/apply_redirects.ts
index cee485c375..0805761d1b 100644
--- a/packages/router/src/apply_redirects.ts
+++ b/packages/router/src/apply_redirects.ts
@@ -18,7 +18,7 @@ import {map} from 'rxjs/operator/map';
 import {mergeMap} from 'rxjs/operator/mergeMap';
 import {EmptyError} from 'rxjs/util/EmptyError';
 
-import {InternalRoute, LoadedRouterConfig, Route, Routes} from './config';
+import {LoadedRouterConfig, Route, Routes} from './config';
 import {RouterConfigLoader} from './router_config_loader';
 import {PRIMARY_OUTLET, Params, defaultUrlMatcher, navigationCancelingError} from './shared';
 import {UrlSegment, UrlSegmentGroup, UrlSerializer, UrlTree} from './url_tree';
@@ -247,7 +247,7 @@ class ApplyRedirects {
   }
 
   private matchSegmentAgainstRoute(
-      ngModule: NgModuleRef<any>, rawSegmentGroup: UrlSegmentGroup, route: InternalRoute,
+      ngModule: NgModuleRef<any>, rawSegmentGroup: UrlSegmentGroup, route: Route,
       segments: UrlSegment[]): Observable<UrlSegmentGroup> {
     if (route.path === '**') {
       if (route.loadChildren) {
@@ -292,8 +292,7 @@ class ApplyRedirects {
     });
   }
 
-  private getChildConfig(ngModule: NgModuleRef<any>, route: InternalRoute):
-      Observable<LoadedRouterConfig> {
+  private getChildConfig(ngModule: NgModuleRef<any>, route: Route): Observable<LoadedRouterConfig> {
     if (route.children) {
       // The children belong to the same module
       return of (new LoadedRouterConfig(route.children, ngModule));
diff --git a/packages/router/src/config.ts b/packages/router/src/config.ts
index b80bf3eb85..de5ef3dbb0 100644
--- a/packages/router/src/config.ts
+++ b/packages/router/src/config.ts
@@ -357,7 +357,10 @@ export interface Route {
   children?: Routes;
   loadChildren?: LoadChildren;
   runGuardsAndResolvers?: RunGuardsAndResolvers;
-  /** @internal */
+  /**
+   * Filled for routes with `loadChildren` once the module has been loaded
+   * @internal
+   */
   _loadedConfig?: LoadedRouterConfig;
 }
 
@@ -365,11 +368,6 @@ export class LoadedRouterConfig {
   constructor(public routes: Route[], public module: NgModuleRef<any>) {}
 }
 
-export interface InternalRoute extends Route {
-  // `LoadedRouterConfig` loaded via a Route `loadChildren`
-  _loadedConfig?: LoadedRouterConfig;
-}
-
 export function validateConfig(config: Routes, parentPath: string = ''): void {
   // forEach doesn't iterate undefined values
   for (let i = 0; i < config.length; i++) {
diff --git a/packages/router/src/recognize.ts b/packages/router/src/recognize.ts
index 169bd84484..684e2c6a1b 100644
--- a/packages/router/src/recognize.ts
+++ b/packages/router/src/recognize.ts
@@ -11,7 +11,7 @@ import {Observable} from 'rxjs/Observable';
 import {Observer} from 'rxjs/Observer';
 import {of } from 'rxjs/observable/of';
 
-import {Data, InternalRoute, ResolveData, Route, Routes} from './config';
+import {Data, ResolveData, Route, Routes} from './config';
 import {ActivatedRouteSnapshot, RouterStateSnapshot, inheritedParamsDataResolve} from './router_state';
 import {PRIMARY_OUTLET, defaultUrlMatcher} from './shared';
 import {UrlSegment, UrlSegmentGroup, UrlTree, mapChildrenIntoArray} from './url_tree';
@@ -154,7 +154,7 @@ function sortActivatedRouteSnapshots(nodes: TreeNode<ActivatedRouteSnapshot>[]):
   });
 }
 
-function getChildConfig(route: InternalRoute): Route[] {
+function getChildConfig(route: Route): Route[] {
   if (route.children) {
     return route.children;
   }
diff --git a/packages/router/src/router.ts b/packages/router/src/router.ts
index f059b39e67..92a815e854 100644
--- a/packages/router/src/router.ts
+++ b/packages/router/src/router.ts
@@ -22,7 +22,7 @@ import {mergeMap} from 'rxjs/operator/mergeMap';
 import {reduce} from 'rxjs/operator/reduce';
 
 import {applyRedirects} from './apply_redirects';
-import {InternalRoute, LoadedRouterConfig, QueryParamsHandling, ResolveData, Route, Routes, RunGuardsAndResolvers, validateConfig} from './config';
+import {LoadedRouterConfig, QueryParamsHandling, ResolveData, Route, Routes, RunGuardsAndResolvers, validateConfig} from './config';
 import {createRouterState} from './create_router_state';
 import {createUrlTree} from './create_url_tree';
 import {RouterOutlet} from './directives/router_outlet';
@@ -1168,7 +1168,7 @@ function advanceActivatedRouteNodeAndItsChildren(node: TreeNode<ActivatedRoute>)
 
 function parentLoadedConfig(snapshot: ActivatedRouteSnapshot): LoadedRouterConfig {
   for (let s = snapshot.parent; s; s = s.parent) {
-    const route: InternalRoute = s._routeConfig;
+    const route = s._routeConfig;
     if (route && route._loadedConfig) return route._loadedConfig;
     if (route && route.component) return null;
   }
@@ -1180,7 +1180,7 @@ function closestLoadedConfig(snapshot: ActivatedRouteSnapshot): LoadedRouterConf
   if (!snapshot) return null;
 
   for (let s = snapshot.parent; s; s = s.parent) {
-    const route: InternalRoute = s._routeConfig;
+    const route = s._routeConfig;
     if (route && route._loadedConfig) return route._loadedConfig;
   }
 
diff --git a/packages/router/src/router_preloader.ts b/packages/router/src/router_preloader.ts
index 7c897c87f8..a4a9177064 100644
--- a/packages/router/src/router_preloader.ts
+++ b/packages/router/src/router_preloader.ts
@@ -16,7 +16,7 @@ import {concatMap} from 'rxjs/operator/concatMap';
 import {filter} from 'rxjs/operator/filter';
 import {mergeAll} from 'rxjs/operator/mergeAll';
 import {mergeMap} from 'rxjs/operator/mergeMap';
-import {InternalRoute, LoadedRouterConfig, Route, Routes} from './config';
+import {LoadedRouterConfig, Route, Routes} from './config';
 import {Event, NavigationEnd, RouteConfigLoadEnd, RouteConfigLoadStart} from './events';
 import {Router} from './router';
 import {RouterConfigLoader} from './router_config_loader';
@@ -100,8 +100,7 @@ export class RouterPreloader implements OnDestroy {
 
   private processRoutes(ngModule: NgModuleRef<any>, routes: Routes): Observable<void> {
     const res: Observable<any>[] = [];
-    for (const r of routes) {
-      const route: InternalRoute = r;
+    for (const route of routes) {
       // we already have the config loaded, just recurse
       if (route.loadChildren && !route.canLoad && route._loadedConfig) {
         const childConfig = route._loadedConfig;
@@ -119,7 +118,7 @@ export class RouterPreloader implements OnDestroy {
     return mergeAll.call(from(res));
   }
 
-  private preloadConfig(ngModule: NgModuleRef<any>, route: InternalRoute): Observable<void> {
+  private preloadConfig(ngModule: NgModuleRef<any>, route: Route): Observable<void> {
     return this.preloadingStrategy.preload(route, () => {
       const loaded$ = this.loader.load(ngModule.injector, route);
       return mergeMap.call(loaded$, (config: LoadedRouterConfig) => {
diff --git a/packages/router/test/apply_redirects.spec.ts b/packages/router/test/apply_redirects.spec.ts
index fb06c2d0cd..5e1e044b1e 100644
--- a/packages/router/test/apply_redirects.spec.ts
+++ b/packages/router/test/apply_redirects.spec.ts
@@ -162,12 +162,12 @@ describe('applyRedirects', () => {
           return of (loadedConfig);
         }
       };
-      const config = [{path: 'a', component: ComponentA, loadChildren: 'children'}];
+      const config: Routes = [{path: 'a', component: ComponentA, loadChildren: 'children'}];
 
       applyRedirects(testModule.injector, <any>loader, serializer, tree('a/b'), config)
           .forEach(r => {
             compareTrees(r, tree('/a/b'));
-            expect((<any>config[0])._loadedConfig).toBe(loadedConfig);
+            expect(config[0]._loadedConfig).toBe(loadedConfig);
           });
     });
 
@@ -289,12 +289,12 @@ describe('applyRedirects', () => {
 
       const loader = {load: (injector: any, p: any) => of (loadedConfig)};
 
-      const config =
+      const config: Routes =
           [{path: '', pathMatch: 'full', redirectTo: '/a'}, {path: 'a', loadChildren: 'children'}];
 
       applyRedirects(testModule.injector, <any>loader, serializer, tree(''), config).forEach(r => {
         compareTrees(r, tree('a'));
-        expect((<any>config[1])._loadedConfig).toBe(loadedConfig);
+        expect(config[1]._loadedConfig).toBe(loadedConfig);
       });
     });
 
@@ -310,7 +310,7 @@ describe('applyRedirects', () => {
         }
       };
 
-      const config = [{path: 'a', loadChildren: 'children'}];
+      const config: Routes = [{path: 'a', loadChildren: 'children'}];
 
       applyRedirects(testModule.injector, <any>loader, serializer, tree('a?k1'), config)
           .subscribe(r => {});
@@ -319,7 +319,7 @@ describe('applyRedirects', () => {
           .subscribe(
               r => {
                 compareTrees(r, tree('a?k2'));
-                expect((<any>config[0])._loadedConfig).toBe(loadedConfig);
+                expect(config[0]._loadedConfig).toBe(loadedConfig);
               },
               (e) => { throw 'Should not reach'; });
     });
@@ -329,10 +329,10 @@ describe('applyRedirects', () => {
 
       const loader = {load: (injector: any, p: any) => of (loadedConfig)};
 
-      const config = [{path: '**', loadChildren: 'children'}];
+      const config: Routes = [{path: '**', loadChildren: 'children'}];
 
       applyRedirects(testModule.injector, <any>loader, serializer, tree('xyz'), config)
-          .forEach(r => { expect((<any>config[0])._loadedConfig).toBe(loadedConfig); });
+          .forEach(r => { expect(config[0]._loadedConfig).toBe(loadedConfig); });
     });
 
     it('should load the configuration after a local redirect from a wildcard route', () => {
@@ -340,11 +340,11 @@ describe('applyRedirects', () => {
 
       const loader = {load: (injector: any, p: any) => of (loadedConfig)};
 
-      const config =
+      const config: Routes =
           [{path: 'not-found', loadChildren: 'children'}, {path: '**', redirectTo: 'not-found'}];
 
       applyRedirects(testModule.injector, <any>loader, serializer, tree('xyz'), config)
-          .forEach(r => { expect((<any>config[0])._loadedConfig).toBe(loadedConfig); });
+          .forEach(r => { expect(config[0]._loadedConfig).toBe(loadedConfig); });
     });
 
     it('should load the configuration after an absolute redirect from a wildcard route', () => {
@@ -352,11 +352,11 @@ describe('applyRedirects', () => {
 
       const loader = {load: (injector: any, p: any) => of (loadedConfig)};
 
-      const config =
+      const config: Routes =
           [{path: 'not-found', loadChildren: 'children'}, {path: '**', redirectTo: '/not-found'}];
 
       applyRedirects(testModule.injector, <any>loader, serializer, tree('xyz'), config)
-          .forEach(r => { expect((<any>config[0])._loadedConfig).toBe(loadedConfig); });
+          .forEach(r => { expect(config[0]._loadedConfig).toBe(loadedConfig); });
     });
   });
 
diff --git a/packages/router/test/integration.spec.ts b/packages/router/test/integration.spec.ts
index c62a56ef55..68612befd8 100644
--- a/packages/router/test/integration.spec.ts
+++ b/packages/router/test/integration.spec.ts
@@ -3049,7 +3049,7 @@ describe('Integration', () => {
                router.navigateByUrl('/blank');
                advance(fixture);
 
-               const config: any = router.config;
+               const config = router.config;
                const firstConfig = config[1]._loadedConfig;
 
                expect(firstConfig).toBeDefined();
diff --git a/packages/router/test/router_preloader.spec.ts b/packages/router/test/router_preloader.spec.ts
index be48638ffe..c1b8d2afd4 100644
--- a/packages/router/test/router_preloader.spec.ts
+++ b/packages/router/test/router_preloader.spec.ts
@@ -10,7 +10,7 @@ import {Compiler, Component, NgModule, NgModuleFactoryLoader, NgModuleRef} from
 import {TestBed, fakeAsync, inject, tick} from '@angular/core/testing';
 
 import {Route, RouteConfigLoadEnd, RouteConfigLoadStart, Router, RouterModule} from '../index';
-import {LoadedRouterConfig} from '../src/router_config_loader';
+import {LoadedRouterConfig} from '../src/config';
 import {PreloadAllModules, PreloadingStrategy, RouterPreloader} from '../src/router_preloader';
 import {RouterTestingModule, SpyNgModuleFactoryLoader} from '../testing';
 
@@ -46,7 +46,7 @@ describe('RouterPreloader', () => {
              tick();
 
              const c = router.config;
-             expect(!!((<any>c[0])._loadedConfig)).toBe(false);
+             expect(c[0]._loadedConfig).not.toBeDefined();
            })));
   });
 
@@ -97,12 +97,12 @@ describe('RouterPreloader', () => {
              const c = router.config;
              expect(c[0].loadChildren).toEqual('expected');
 
-             const loadedConfig: LoadedRouterConfig = (<any>c[0])._loadedConfig;
+             const loadedConfig: LoadedRouterConfig = c[0]._loadedConfig;
              const module: any = loadedConfig.module;
              expect(loadedConfig.routes[0].path).toEqual('LoadedModule1');
              expect(module.parent).toBe(testModule);
 
-             const loadedConfig2: LoadedRouterConfig = (<any>loadedConfig.routes[0])._loadedConfig;
+             const loadedConfig2: LoadedRouterConfig = loadedConfig.routes[0]._loadedConfig;
              const module2: any = loadedConfig2.module;
              expect(loadedConfig2.routes[0].path).toEqual('LoadedModule2');
              expect(module2.parent).toBe(module);
@@ -165,12 +165,12 @@ describe('RouterPreloader', () => {
 
              const c = router.config;
 
-             const loadedConfig: LoadedRouterConfig = (<any>c[0])._loadedConfig;
+             const loadedConfig: LoadedRouterConfig = c[0]._loadedConfig;
              const module: any = loadedConfig.module;
              expect(module.parent).toBe(testModule);
 
-             const loadedConfig2: LoadedRouterConfig = (<any>loadedConfig.routes[0])._loadedConfig;
-             const loadedConfig3: LoadedRouterConfig = (<any>loadedConfig2.routes[0])._loadedConfig;
+             const loadedConfig2: LoadedRouterConfig = loadedConfig.routes[0]._loadedConfig;
+             const loadedConfig3: LoadedRouterConfig = loadedConfig2.routes[0]._loadedConfig;
              const module3: any = loadedConfig3.module;
              expect(module3.parent).toBe(module2);
            })));
@@ -204,8 +204,8 @@ describe('RouterPreloader', () => {
              tick();
 
              const c = router.config;
-             expect(!!((<any>c[0])._loadedConfig)).toBe(false);
-             expect(!!((<any>c[1])._loadedConfig)).toBe(true);
+             expect(c[0]._loadedConfig).not.toBeDefined();
+             expect(c[1]._loadedConfig).toBeDefined();
            })));
   });
 });